THOMPSON, Chief Justice.

These cases present constitutional and statutory questions arising from the use of private probation companies by Georgia courts to provide misdemeanor probation supervision services. Thirteen plaintiffs filed individual civil actions against Sentinel Offender Services, LLC, a private for-profit probation servicing entity, and other defendants seeking declaratory and injunctive relief and damages based on claims that Sentinel unlawfully collected probation supervision fees from plaintiffs and violated their due process rights.1 Among other things, the plaintiffs: (1) challenged the constitutionality of OCGA § 42-8-100(g)(1), Georgia's private probation statute; (2) alleged that OCGA § 42-8-30.1 precludes tolling of misdemeanor probation sentences and restricts the conditions that may be imposed on probationers in misdemeanor cases including that electronic monitoring is not allowed; (3) challenged Sentinel's authority to provide misdemeanor probation services to the Superior Court of Columbia County; and (4) sought to recover from Sentinel probation supervision fees plaintiffs contend Sentinel unlawfully collected from them and other damages. All thirteen actions were assigned as companion cases to Superior Court Judge Daniel J. Craig of the Augusta Judicial Circuit, who conducted joint hearings on various motions filed by the individual plaintiffs and by Sentinel.2

On appeal are two consolidated orders entered contemporaneously by the trial court in the pending cases. The trial court issued one order in the five Columbia County cases and another in the eight Richmond County cases. While the two orders differ somewhat with respect to the trial court's findings of fact specific to the cases filed in each county, the trial court determined certain issues of law and fact were common to all the cases before it and entered identical rulings in both orders on these issues. See OCGA § 9-11-42(a). "It is well settled that a court may take judicial notice of its own records in the immediate case or proceedings before it." Baker v. City of Atlanta, 211 Ga. 34, 83 S.E.2d 682 (1954) (quoting from Branch v. Branch, 194 Ga. 575, 577, 22 S.E.2d 124 (1942)). As it appears from the record that the parties acquiesced in the trial court's consolidation of these issues,3 the trial court was entitled to consider the evidence presented in all thirteen companion cases when ruling on the motions before it. See OCGA § 9-11-42(a). The trial court's consolidation of these issues has not been specifically challenged by the parties on appeal. See Ford v. Uniroyal Goodrich Tire Co., 267 Ga. 226, 229 n. 12, 476 S.E.2d 565 (1996).

Among other things, the trial court held that OCGA § 42-8-100(g)(1) was not unconstitutional on its face and did not offend due process or equal protection nor condone imprisonment for debt; ruled that the statutory framework prohibited private probation services from having the sentences of misdemeanor probationers tolled or from collecting fees for electronic monitoring; found the plaintiffs had a right to recover from Sentinel any statutorily unauthorized probation supervision fees Sentinel had collected from them; and, with respect to the Columbia County plaintiffs, determined that although Sentinel's contract with the superior court of that county had not been properly approved by the county governing authority as statutorily required, mutual mistake and principles of equity prevented Sentinel from having to disgorge any probation supervision fees which would have been lawful for Sentinel to collect under a valid contract. Procedurally, the trial court denied Sentinel's motions to dismiss and motion for judgment on the pleadings,4 granted in part and denied in part Glover's motion for partial summary judgment, conditionally certified class actions in each county, and granted injunctive relief to the plaintiffs.

All in all, 32 appeals and cross-appeals have been filed in this Court seeking review of these orders.5 Appellants Sentinel Offender Services, LLC, Christina Kapral, Gina A. Childs, Martin M. Murray, Cheryl Bryant and Kayla White (hereinafter collectively referred to as "Sentinel") appeal from the trial court's grant of summary judgment and injunctive relief in each of the thirteen cases as well as from the court's conditional certification of class actions in both Columbia and Richmond counties.6 Appellant Richard Roundtree, Sheriff of Richmond County, Georgia (hereinafter "Roundtree"), named as a defendant in five of the Richmond County cases and permitted by the trial court to intervene in a sixth, filed separate appeals from the injunctive relief granted in those six cases. Finally, all thirteen plaintiffs, Jacob Martin Glover, Willie James Gilyard, Pamela Lynn Tennille, Brandon Tyler Osborn, Lawrence Ruben Martin, Jr., Virginia Cash, Kelvin Ashley, Clifford Hayes, Amanda Stephens, Thomas John Barrett, William Stephen Carter, Kathleen Myrtle Hucks and Nathan Ryan Mantooth, filed individual cross-appeals from the orders entered in their respective cases.

Each of the cases on appeal involves a plaintiff who was convicted of at least one misdemeanor in either Columbia County Superior Court7 or Richmond County State Court and received a probated sentence which resulted in his or her paying probation supervision fees to Sentinel. The plaintiffs, none of whom directly appealed their misdemeanor convictions or, where probation was revoked, sought discretionary review of their probation revocations, instead filed civil actions in the superior court seeking injunctive relief and damages against Sentinel.

All five of the Columbia County plaintiffs, Glover, Gilyard, Tennille, Osborn and Martin, alleged Sentinel's contract to provide probation services to the Columbia County Superior Court was invalid due to Sentinel's failure to secure approval from the Columbia County Commission as required by OCGA § 42-8-100(g)(1) and Glover filed his complaint as a class action additionally challenging the constitutionality of OCGA § 42-8-100(g)(1).8 Two plaintiffs also alleged that Sentinel illegally modified the terms and conditions of their sentences by adding conditions such as drug screens and treatment programs not included in their original court ordered sentences and swore out warrants for their arrest based, in part, on their failure to comply with these added conditions, while three claimed Sentinel illegally collected or sought to collect excessive supervision fees from them by seeking probation revocation warrants against them after their original probation terms had expired.9

The eight Richmond County plaintiffs, Cash, Ashley, Hayes, Stephens, Barrett, Carter, Hucks and Mantooth, made similar claims against Sentinel. Along with challenging the constitutionality of OCGA § 42-8-100(g)(1), several plaintiffs claimed Sentinel illegally collected excessive supervision fees from them through the unlawful tolling of their misdemeanor sentences and for electronic monitoring and drug and alcohol testing not authorized by the private probation statutory framework. Three of the plaintiffs alleged that the contract between Sentinel and the State Court of Richmond County, Georgia, was illegal and void under OCGA § 13-8-2(a)(1) as one tending to corrupt the judiciary and two plaintiffs additionally sought to challenge the provisions of OCGA § 15-21A-6 (c) as violating Georgia's constitutional guarantee of the right to counsel. See Alford v. State, 287 Ga. 105, 695 S.E.2d 1 (2010). Further, four plaintiffs who were in custody at the time, and one about to be incarcerated, filed their actions as petitions for habeas corpus claiming that the revocations of their probation had been unconstitutional and in violation of the mandates of the United States Supreme Court in Bearden v. Georgia, 461 U.S. 660, 103 S.Ct. 2064, 76 L.Ed.2d 221 (1983) and the Georgia Court of Appeals in Johnson v. State, 307 Ga.App. 570, 707 S.E.2d 373 (2011) in that no inquiry had been made as to whether they had wilfully violated the terms of their probation or if they were being held in custody for fines they could not pay.10 Subsequently, the trial court granted habeas relief to these plaintiffs based on the court's determination that they had entered guilty pleas without being afforded the colloquy required by Boykin v. Alabama, 395 U.S. 238, 89 S.Ct. 1709, 23 L.Ed.2d 274 (1969), but refused to dismiss their civil claims against Sentinel.11 Finally, one of the plaintiffs, Mantooth, filed a class action complaint seeking declaratory and injunctive relief pursuant to OCGA § 9-11-23(b)(1) and (b)(3).12

Although the facts in the individual cases have not been fully developed given the procedural posture of the appeals before us, we find the legal issues on appeal and cross-appeal were properly raised in some, if not all, of the cases below.13 We further note that all of the trial court's substantive rulings have been challenged on appeal by either the appellants or cross-appellants. Specific facts relied on by this Court will be identified as necessary.14 For the reasons which follow, we affirm in part and reverse in part the judgments of the trial court, and we remand the cases with direction.

1. As a preliminary matter, we note that little focus has been placed on the justiciability of the various claims raised by the individual plaintiffs in these cases. After careful review of the records and briefs, we have determined that at least one plaintiff presents in a properly justiciable form each of the substantive legal issues that the trial court decided in its consolidated orders and that we decide below. On remand, however, the trial court is directed to consider the justiciability of each claim as raised by each plaintiff or as applicable to other persons affected by any injunctive or class relief.

We find no merit to the blanket contention by Sentinel that all the plaintiffs are precluded from bringing civil actions against it for money had and received, false arrest, and injunctive relief due to their failure to appeal their underlying criminal convictions and sentences. With respect to the Columbia County plaintiffs, the record clearly establishes that prior to the filing of these cases in 2012, no misdemeanor sentence imposed by the Superior Court of Columbia County designated Sentinel as the supervising probation service. Instead, all of the misdemeanor sentences imposed on the plaintiffs by the courts of that county referred only to the "State Probation Office." Thus, at the time of conviction or revocation for these Columbia County plaintiffs there existed no basis for them to appeal their validly imposed sentences on the grounds that probation supervision by private companies is facially unconstitutional or that the county did not have a valid contract with Sentinel. See Owens v. Hill, 295 Ga. 302, 305(2), 758 S.E.2d 794 (2014) (where criminal defendant faces allegedly illegal conduct related to the implementation of his or her sentence which cannot be challenged through a direct appeal of the conviction and sentence or through a habeas corpus action, declaratory or injunctive relief may be sought in a collateral civil action).

Likewise, to the extent that the Columbia County and Richmond County plaintiffs' claims are based not on their criminal judgments or on what those judgments directed Sentinel to do, res judicata would not bar these claims. See id. This would include claims based on Sentinel's allegedly tortious conduct in falsely swearing out probation revocation warrants against plaintiffs after the payment of all fines, costs, and restitution or the expiration of their sentences, or swearing out warrants based on a plaintiff's failure to comply with probation conditions not imposed by the sentencing court but rather unilaterally added by Sentinel; however, we note that, to the extent that the plaintiffs challenge Sentinel's allegedly tortious conduct that was not authorized by the sentencing court, the trial court did not decide those claims and we do not decide them either.

On the other hand, where a plaintiff's claim could have been raised in a direct appeal, res judicata normally would preclude the same claim from being raised against the State or its privies, including persons or entities executing the judgment, in a subsequent civil action, although claims based on an allegedly illegal sentence might be raised in the sentencing or habeas court, if they have not become moot.15 See Div. 4(c), infra. The trial court should address these res judicata issues with respect to each plaintiff's specific claims on remand. The proper application of these principles should mean that the civil court's order, and particularly any equitable relief granted, does not directly conflict with the prior judgment of the criminal court, although there may be incidental effects. See Owens v. Hill, supra; OCGA § 9-5-2.

In addition, on remand the trial court must address justiciability questions regarding the court's jurisdiction to address each claim raised by each plaintiff, including standing,16 ripeness17 and mootness.18

2. Turning to the substantive challenges raised, we first address plaintiffs' constitutional challenge to OCGA § 42-8-100(g)(1), Georgia's private probation statute, which provides, in pertinent part:

Plaintiffs contend this statute is facially invalid because it allows courts to contract with private, for-profit entities to provide probation supervision services to misdemeanor probationers without setting forth any guidelines for contractual requirements regarding how these companies are to be paid and without placing any limitations or restrictions on the cost or amount of fees which can be passed on to the public. Plaintiffs assert that, as a result, the statute improperly allows courts to delegate the provision of probation services to private companies whose employees act as officers of the court, but who owe a duty of loyalty to the for-profit companies which employ them. Plaintiffs argue that by permitting courts to outsource probation supervision services to private, for-profit entities, this statute deprives misdemeanor probationers of their constitutional rights to due process of law and equal protection under the Georgia Constitution of 1983, Art. I, Sec. I, Par. I and II, while condoning imprisonment for debt in violation of the Georgia Constitution of 1983, Art. I, Sec. I, Par. XXIII.

Plaintiffs claim that the statute is unconstitutional on its face because the privatization of probation supervision services systemically denies misdemeanor probationers of their liberty or property without due process of law. We disagree.

(a) In addressing plaintiffs' facial challenge to the constitutionality of the private probation statute, we are cognizant of the fact that

(Citations and punctuation omitted.) JIG Real Estate, LLC v. Countrywide Home Loans, Inc., 289 Ga. 488, 490(2), 712 S.E.2d 820, 823 (2011). Moreover, where, as here, a party's First Amendment rights are not implicated, the party mounting the challenge can succeed only "by establish[ing] that no set of circumstances exists under which the statute would be valid, i.e., that the law is unconstitutional in all of its applications, or at least that the statute lacks a plainly legitimate sweep." (Citation and punctuation omitted.) Blevins v. Dade County Bd. of Tax Assessors, 288 Ga. 113, 118(3), 702 S.E.2d 145 (2010).

On its face, OCGA § 42-8-100(g)(1) simply gives courts the authority to contract with private providers for the administration of probation services. Plaintiffs contend, however, that because the statute does not limit or restrict the manner in which courts contract with these private entities, the statute allows courts to contract with private companies in a manner which ties company profits to how long a misdemeanant is kept on probation and how many services such as electronic monitoring or drug screening are imposed, thus creating a conflict of interest for company employees acting as private probation officers and serving as officers of the court.19 See Wolcott v. State, 278 Ga. 664, 665, 604 S.E.2d 478 (2004) ("[P]robation officer's primary duty is to represent the interest of justice and not the interest of his or her employer."); Huzzie v. State, 253 Ga.App. 225, 226, 558 S.E.2d 767 (2002) (probation officers aid sentencing courts by serving as an investigative and supervisory arm of the court). Plaintiffs assert that because sentencing courts rely on the recommendations of private probation officers who have a pecuniary interest in recommending one course of action to the court over another, probationers' due process rights to fair, impartial tribunals, untainted by conflicting financial interests, are violated. Further, plaintiffs assert that under the private probation system thus created, courts are encouraged by private probation officers to impose excessive and improper probation supervision services on probationers who subsequently are imprisoned when they are unable to pay the fees associated with the supervision services imposed.

While the supervision of probation is a function historically performed by state probation officers, the mere act of privatizing these services does not violate due process. Nothing on the face of the statute allows Sentinel or any other private probation company to deprive an individual of his or her property or liberty without due process of law nor is there anything which authorizes the creation of a private probation system that is so fundamentally unfair that it fails to comport with our notions of due process. The due process clause does not prohibit the State from entering into a contract with a private entity for the provision of probation supervision services but requires that when it chooses to do so the State continue to provide due process to individuals under its supervision. As found by the trial court, most of the injuries alleged by the plaintiffs in these cases occurred not because of Sentinel's compliance with the restrictions placed upon it by the private probation statutory framework, but because of Sentinel's failure or the failure of its employees to abide by the limited statutory authority granted.

Importantly, under this framework it is the sentencing court which decides whether or not to probate a defendant's sentence and determines the conditions under which such probation shall occur. See OCGA § 17-10-1(a)(1). Further, it is the sentencing court which bears the responsibility for determining whether a probationer has the ability to make court-ordered payments, including the payment of fees, and to consider alternative measures of punishment other than imprisonment where a probationer is unable to do so. See Bearden, supra, 461 U.S. at 672, 103 S.Ct. 2064 (if probationer is unable to pay despite bona fide efforts, the sentencing court must consider alternative measures of punishment other than imprisonment); Johnson v. State, supra, 307 Ga.App. at 573, 707 S.E.2d 373; McMahon v. State, 284 Ga.App. 192, 194, 643 S.E.2d 236 (2007) (should defendant be unable to pay, the protection of his constitutional rights will be governed by the principles in Bearden). Nothing on the face of the statute allows for the imposition of unreasonable or illegal fees on probationers by the sentencing court, nor permits the court to improperly delegate its duties under Bearden to probation officers. Accordingly, while we are concerned by the allegations made and evidence presented in these cases, we agree with the trial court that most of the alleged injuries suffered by the plaintiffs are not a consequence of the privatization of probation services per se, but rather result from wrongful acts allegedly committed by Sentinel employees.

(b) To the extent plaintiffs argue that the statute is unconstitutional as applied, we find the trial court did not distinctly rule on this issue in its orders. Despite expressing concern over Sentinel's treatment of alleged probation violators and the manner in which Sentinel sought probation revocations, the trial court concluded that any injuries or takings by Sentinel under the auspices of its role as probation supervisor had not been authorized by the statute. This Court will not rule on a constitutional question "unless it clearly appears in the record that the point was directly and properly made in the court below and distinctly passed on by the trial judge." Pitts v. G.M.A.C., 231 Ga. 54, 56, 199 S.E.2d 902 (1973). As the trial court did not address plaintiffs' constitutional challenges to the statute as applied, these arguments cannot be considered in this appeal. See Marks v. State, 280 Ga. 70(4), 623 S.E.2d 504 (2005).

(c) We agree with the trial court that the statute does not on its face unconstitutionally condone imprisonment for debt. As noted by the trial court, all the plaintiffs in these actions were convicted of misdemeanors and placed on probation as an alternative to incarceration. See Tuttle v. State, 215 Ga.App. 396, 397, 450 S.E.2d 863 (1994). This Court has recognized a distinction between imprisonment for debt and imprisonment for criminal behavior. See Connally v. State, 265 Ga. 563, 458 S.E.2d 336 (1995) (Georgia constitution does not forbid imprisonment for criminal conduct, even though the criminal conduct also results in a civil debt). Accordingly, we hold the statute does not on its face condone imprisonment for debt as alleged by the plaintiffs.

3. In ruling on plaintiffs' challenge to OCGA § 42-8-100(g)(1), the trial court determined as a matter of law that the private probation statutory framework prohibits the tolling of sentences imposed on defendants supervised by private probation servicing entities and also prohibits the imposition on these defendants of any conditions of probation statutorily reserved to the State Department of Corrections (hereinafter the "DOC"). We now review these rulings.

(a) Article 2. The administration of probation in this State is governed by Chapter 8 of Title 42 of the Official Code of Georgia Annotated, the provisions of which are divided into Articles 1 through 9. Article 2,20 also known as the "State-wide Probation Act," sets forth a state-wide probation system created for felony offenders "to be administered by the Department of Corrections." OCGA § 42-8-22. OCGA § 42-8-30.1 which is located in Article 2, provides:

(Emphasis supplied.) Based on this statutory language, the trial court determined that none of the provisions of Article 2, including OCGA § 42-8-36, which allows probationers' sentences to be tolled under certain circumstances,21 and OCGA § 42-8-35(a)(14), which permits a court to impose electronic monitoring as a condition of probation, were applicable to misdemeanor probationers supervised by private probation officers.22

Sentinel and Roundtree assert that the statutory language of OCGA § 42-8-30.1 should be interpreted to render only certain provisions of Article 2 inapplicable to misdemeanor defendants.23 They argue that the trial court's interpretation is improper in that it relegates the descriptive phrase "relating to probation supervision services" to mere surplusage. We disagree.

Atlanta Independent School System v. Atlanta Neighborhood Charter School, Inc., 293 Ga. 629, 631, 748 S.E.2d 884 (2013).

(Citations and punctuation omitted.) Chase v. State, 285 Ga. 693, 695-696(2), 681 S.E.2d 116 (2009).

In determining the proper meaning of "relating to probation supervision services," as used in the statute, we note that the phrase "probation supervision services" is not defined in either the Code or case law. Based on our review of Article 2, we find it difficult to determine which provisions contained therein would fall within the limited exclusion proposed by appellants. Indeed, a close examination of Article 2 reveals that there are no whole sections of that article, and not even whole subsections, that appear clearly limited to supervision "services." Given the difficulties that arise in trying to read "probation supervision services" as relating only to certain provisions of Article 2, it is doubtful that the General Assembly intended for such an interpretation. When read along with the rest of Article 2 and the Code as a whole, OCGA § 42-8-30.1 is most naturally interpreted so that the phrase "relating to probation supervision services" describes "this article" rather than particular "provisions of this article." It was not meaningless surplusage to include a general description of "this article," particularly as OCGA § 42-8-30.1 was not enacted or amended along with the rest of Article 2, and the General Assembly has used similar formulations elsewhere in the Code. See, e.g., OCGA §§ 10-2-22, 40-1-55. Accordingly, we agree with the trial court that none of the provisions of the State-wide Probation Act are applicable to defendants sentenced in courts utilizing probation systems authorized by OCGA § 42-8-100(g)(1).

Our inquiry does not end here, however, as we must determine whether any authority exists outside the provisions of Article 2 for the application of tolling or electronic monitoring to misdemeanor probationers.

(b) Tolling. We agree with the trial court that under current Georgia statutes, the tolling of a misdemeanor probationer's sentence is not permitted. "Statutes providing for the suspension of a sentence or the probation of a defendant must be strictly followed." Cross v. Huff, 208 Ga. 392, 396, 67 S.E.2d 124 (1951); Entrekin v. State, 147 Ga.App. 724 (250 S.E.2d 177 (1978)). See also Tenney v. State, 194 Ga.App. 820, 392 S.E.2d 294 (1990). As found above, courts utilizing probation systems established pursuant to OCGA § 42-8-100(g)(1) are specifically precluded from applying the provisions of the State-wide Probation Act, including those pertaining to tolling, to the defendants they sentence and we find no other grounds for such activity under Georgia statutory law. Unlike the statutes governing the supervision of felony probationers by the state DOC, there is no statute governing misdemeanor probationers which specifically authorizes the tolling of a probationer's sentence.24 Rather, with respect to a misdemeanor conviction, sentences are fixed at one year and once a sentence has been served, jurisdiction over the defendant ceases. See OCGA § 17-10-3; State v. Mills, 268 Ga. 873, 874, 495 S.E.2d 1 (1998) (requiring State to seek probation revocation within the period of probation as required by statute); State v. Mohamed, 203 Ga.App. 21, 416 S.E.2d 358 (1992).

Accordingly, we affirm the trial court's holding that the private probation statutory framework does not allow for the tolling of misdemeanor probationers' sentences.25 To the extent Georgia courts have recognized OCGA § 42-8-36 as a basis for allowing courts utilizing probation systems established pursuant to OCGA § 42-8-100(g)(1) to toll a probationer's sentence, such analysis was in error and hereby is disapproved. See, e.g., Wilson v. State, 292 Ga.App. 540, 664 S.E.2d 890 (2008); Vincent v. State, 271 Ga.App. 138, 608 S.E.2d 748 (2004).

(c) Electronic monitoring. Electronic monitoring is a condition of probation which does not necessarily require explicit statutory authority in order to be imposed. See Ballenger v. State, 210 Ga.App. 627, 628, 436 S.E.2d 793 (1993). OCGA § 17-10-1(1)(a) permits a sentencing judge to suspend or probate all or any part of a defendant's sentence "under such rules and regulations as the judge deems proper." Judges operating within Georgia's private probation statutory framework retain this power. See OCGA § 42-8-100(c) and (e). The only restriction on a sentencing court is that the conditions of probation it imposes be reasonable. See State v. Pless, 282 Ga. 58, 60, 646 S.E.2d 202 (2007) (probation and suspension statutes vest broad discretion in trial judges to impose any reasonable condition of probation); Penaherrera v. State, 211 Ga.App. 162, 163, 438 S.E.2d 661 (1993). Accordingly, we find the trial court erred in holding that the imposition of electronic monitoring on misdemeanor defendants is prohibited. The fact that electronic monitoring and other conditions of probation are described in Article 2 as acceptable sentencing options for felony probationers supervised by the DOC, does not, in and of itself, prohibit the application of these conditions to misdemeanor probationers supervised by private probation servicing companies.

4. Having affirmed the trial court's rulings with respect to the constitutionality of OCGA § 42-8-100(g)(1) and having addressed the proper statutory interpretation of OCGA § 42-8-30.1, we now consider whether the trial court erred in finding that the plaintiffs have a right of recovery against Sentinel under the doctrine of money had and received for any probation supervision fees Sentinel collected from the plaintiffs that were not lawfully imposed.

(a) The trial court granted Glover's motion for partial summary judgment and denied Sentinel's motion for judgment on the pleadings with respect to the plaintiffs' right to bring a claim against Sentinel for money had and received. Specifically, the trial court found plaintiffs had a right of recovery as to any fees they paid to Sentinel for probation supervision services rendered after their original sentences had expired or for electronic monitoring.

Sentinel argues the plaintiffs have no private right of action to challenge the validity of its contracts to provide private probation services to the Columbia County and Richmond County courts or to seek the return of probation supervision fees plaintiffs were ordered to pay by the sentencing court. Plaintiffs, on the other hand, assert Sentinel was unjustly enriched at their expense when it collected probation supervision fees from them in excess of those authorized by the sentencing court or which were authorized by the court unlawfully and contend that they are entitled to recover these fees from Sentinel.26

Haugabook v. Crisler, 297 Ga.App. 428, 431, 677 S.E.2d 355 (2009) (quoting Jasper School Dist. v. Gormley, 184 Ga. 756, 758, 193 S.E. 248 (1937)).

In general, we agree with the trial court's determination that a cause of action based on the theory of money had and received could be brought against Sentinel to recover probation supervision fees which it unlawfully collected from misdemeanor probationers in contravention of the dictates of the private probation statutory framework approved by the Georgia legislature. The evidence shows that Sentinel entered into, or attempted to enter into, "no-cost" contracts with the Columbia County and Richmond County courts pursuant to which Sentinel agreed to charge the courts nothing for probation services and to instead collect probation supervision fees directly from misdemeanor probationers. As a result, Sentinel placed itself in the position of potentially receiving and retaining money from the plaintiffs which the plaintiffs were not lawfully required to pay and which Sentinel was not lawfully entitled to receive. It is immaterial for purposes of plaintiffs' right to recover these fees from Sentinel that the sentencing court wrongly believed it had the statutory authority to impose these fees. We find error, however, in the trial court's application of this ruling to the specific facts before it.

(b) With respect to the Columbia County plaintiffs' ability to recover probation supervision fees paid to Sentinel under the terms of an invalid contract, we find the trial court erred in holding that the doctrine of mutual mistake and the principles of equity prevent Sentinel from having to disgorge any probation supervision fees Sentinel collected from them which the sentencing court had the ability to lawfully impose. Under Georgia law, a private probation company can act as a probation provider and its employees may serve as probation officers only if the company complies with the terms and provisions of OCGA § 42-8-100(g)(1). This statute states in pertinent part:

That the statute contemplates county approval of the actual contract for such services rather than approval for the privatization of probation services in general is evidenced by the statutory language immediately following which provides:

Because the record supports the trial court's finding that there never was an approved contract for probation services between Sentinel and the Columbia County governing authority within the contemplation and provisions of the statute, we agree that Sentinel's contract with Columbia County is invalid.27

Purported contracts with public entities that are entered without observance of the legal requirements are ultra vires and void. See City of Baldwin v. Woodard & Curran, Inc., 293 Ga. 19, 27-29, 743 S.E.2d 381 (2013) (contract with the city which had not been properly approved as required by the city charter was ultra vires and void); H.G. Brown Family Ltd. Partnership v. City of Villa Rica, 278 Ga. 819, 820, 607 S.E.2d 883 (2005). Without a valid contract, Sentinel lacked the statutory authority to provide probation supervision services to the Superior Court of Columbia County and thus had no right to collect probation supervision fees from the plaintiffs.

Despite properly finding that Sentinel's contract with Columbia County was invalid, the trial court determined there was a mutual mistake on the part of both Sentinel and the Columbia County courts regarding the omission to secure approval for the contract from the governing authority, thus the principles of equity would apply to allow Sentinel to retain unauthorized fees it had collected. This holding is in error. See City of Baldwin, supra at 28, 743 S.E.2d 381 (recovery under an equitable doctrine not allowed where contract is ultra vires and void even though party seeking recovery has performed its part of the bargain and relied upon the contract to its detriment). Just as equity would not be available to aid Sentinel in recovering payment for the performance of probation supervision services under the void contract, equity will not protect Sentinel from having to disgorge that which it unlawfully received. Nor can Sentinel rely on the fact that the plaintiffs were ordered by the court to pay probation supervision fees as justification for its retention of fees it illegally collected. Absent a valid contract, it similarly was not within the lawful power of the Columbia County courts to require probationers to submit to probation supervision provided by Sentinel or any other unauthorized person or entity, thus it was unlawful for Sentinel to extract payment from the plaintiffs for the performance of these services.

Accordingly, the trial court erred in holding Sentinel would not be required to disgorge probation supervision fees it collected from the Columbia County plaintiffs under an invalid contract.

(c) In the Richmond County cases, the validity and proper execution of Sentinel's contract to provide private probation services to the Richmond County State Court was not at issue. Because Sentinel was an authorized private probation service provider in Richmond County pursuant to a valid contract, the trial court determined that the Richmond County plaintiffs had no right of recovery against Sentinel for any probation supervision fees they paid during the original terms of their probated sentences, but did have a right of recovery against Sentinel for any probation fees they paid after the expiration of the term of their original sentences or for electronic monitoring. While we agree with the trial court that a potential cause of action under a theory of money had and received exists for these plaintiffs to recover such fees paid after the expiration of their original sentences, see Div. 3(b) supra, we note that the justiciability of each plaintiff's claim in the trial court would be dependent on the particular facts of his or her case, including whether or not these additional fees were paid following a revocation hearing and pursuant to a court order which could have been appealed or were paid without benefit of a hearing or entry of an appealable order. To the extent a plaintiff was required to pay additional unauthorized fees pursuant to an appealable criminal court order, that order cannot be collaterally challenged. However, such plaintiffs might return to the sentencing court to challenge their sentence as illegal or possibly seek relief through the filing of a habeas corpus petition,28 with the potential to recover monies paid pursuant to an illegal sentence. See Nazario v. State, 293 Ga. 480, 488, 746 S.E.2d 109 (2013); Williams v. State, 287 Ga. 192, 193, 695 S.E.2d 244 (2010); Harper v. State, 286 Ga. 216, 217 n. 1, 686 S.E.2d 786 (2009). Compare Colorado v. Noel, 134 P.3d 484 (Colo. App.2005) (defendant not entitled to refund of probation supervision fees where conviction vacated) with Cooper v. Gordon, 389 So.2d 318, 319 (Fla. 3rd DCA 1980) (probation service fees paid under a reversed conviction may be recoverable).

(d) Finally, we reverse the trial court's ruling with respect to any electronic monitoring fees imposed by the sentencing court and collected by Sentinel for monitoring services rendered during a probationer's original term of sentence. See Div. 3(c) supra. Only where electronic monitoring was unlawfully imposed by the court on a misdemeanor probationer after the expiration of his or her original sentence would such fees potentially be recoverable.

5. Sentinel challenges the trial court's certification of class actions against it in both Columbia and Richmond counties. In Columbia County, Glover moved pursuant to OCGA § 9-11-23(b)(3) for certification of a class of plaintiffs seeking the recovery of probation supervision fees paid to Sentinel asserting both that Sentinel lacked a valid contract with the Columbia County Superior Court to provide probation supervision services and that Georgia's private probation statute, OCGA § 42-8-100(g)(1), was unconstitutional. In Richmond County, Mantooth filed suit against Sentinel for false arrest and imprisonment in Richmond County Superior Court claiming Sentinel employees wrongfully swore out a warrant for his arrest in order to collect probation supervision fees from him to which Sentinel was not entitled because he had fully paid his fine and completed the terms of his probation. In his action, Mantooth sought certification of a class for declaratory and injunctive relief pursuant to OCGA § 9-11-23(b)(1) and (b)(2) to enjoin Sentinel from unlawfully causing arrest warrants to be issued against misdemeanor probationers. The trial court noted that all the plaintiffs could be considered members of the classes described by Glover and Mantooth and conditionally granted Glover's motion for class certification pursuant to OCGA § 9-11-23(b)(3) as well as the class-wide declaratory and injunctive relief sought by Mantooth.

Granting Glover's motion for class certification, the trial court included all the plaintiffs in the companion cases as putative class members by conditionally certifying classes in both Columbia and Richmond counties. Consistent with its decisions on the constitutional, statutory and legal issues presented, the trial court conditionally certified a class in Columbia County consisting of "persons who have paid any fees to Sentinel after expiration of the original term of their sentences" but deferred ruling on whether Glover was a proper class representative and whether proceedings on behalf of the class should be proved in Columbia County Superior Court or Richmond County Superior Court. In Richmond County, the trial court conditionally certified a class consisting of "persons who have paid any fees to Sentinel after expiration of the original term of their sentences or who have paid Sentinel for electronic monitoring at any time during their probation," and designated Mantooth as the class representative.

Sentinel complains that the trial court's class certifications were in error while the plaintiffs assert this issue is not ripe for review by this Court given that class certification was only conditionally granted and the trial court deferred ruling on several important issues. "Whether to certify a class is a matter committed to the discretion of the trial court." Georgia-Pacific Consumer Products, LP v. Ratner, 295 Ga. 524, 762 S.E.2d 419 (2014). On appellate review, this Court will respect the discretion of the trial judge in certifying or refusing to certify a class action where that discretion has not been abused. See State Farm Mut. Auto. Ins. Co. v. Mabry, 274 Ga. 498, 499-500(1), 556 S.E.2d 114 (2001). We, however, do not in these appeals address the propriety of the trial court's conditional grants of class certification because the trial court's grant of such relief was based on rulings which have been reversed or are otherwise affected by our decision today. Accordingly, those parts of the trial court's orders conditionally certifying class actions in Columbia and Richmond counties are reversed and the cases remanded to the trial court for reconsideration of the class certification issues in light of this opinion. In doing so, the trial court must carefully consider issues of justiciability with respect to the scope of any class certified and the relief available to potential class members. See Div. 1, supra.

6. Finally, Sentinel and Sheriff Roundtree contend the trial court erred by granting permanent injunctive relief enjoining them from requiring probationers to submit to any condition of probation reserved in Article 2 to the DOC and from taking any action to supervise or enforce the conditions of any probated sentence after the expiration of its original term. The decision whether to grant a request for injunctive relief rests in the sound discretion of the trial judge according to the circumstances of each case, and a reviewing court will not reverse the trial court's decision absent an error in the law contributing to that decision, a manifest abuse of discretion, or a finding of no evidence on which to base the trial court's ruling. See OCGA § 9-5-8; Chambers v. Peach County, 268 Ga. 672(1), 492 S.E.2d 191 (1997). But see OCGA § 9-5-2 ("Equity will take no part in the administration of the criminal law. It will neither aid criminal courts in the exercise of their jurisdiction, nor will it restrain or obstruct them."). As with the class certification issues, we do not in these appeals address the propriety of the trial court's grant of injunctive relief because the trial court's grant of such relief was based on its rulings regarding Sentinel's authority to toll a probationer's sentence and impose conditions of probation under OCGA § 40-8-30.1, rulings which have been reversed or are otherwise affected by our decision today. Accordingly, those parts of the trial court's orders granting injunctive relief are reversed and the cases are remanded to the trial court for reconsideration of plaintiffs' requests for injunctive relief in light of this opinion. Again, we advise the trial court to carefully consider issues of justiciability in considering such requests. See Div. 1, supra.

Judgments in Case Nos. S14A1033, S14X1034, S14A1035, S14X1036, S14A1037, S14X1038, S14A1039, S14X1040, S14A1041, S14X1042 affirmed in part, reversed in part and remanded with direction.

Judgments in Case Nos. S14A1251, S14X1252, S14A1253, S14A1254, S14X1255, S14A1256, S14A1257, S14X1258, S14A1259, S14A1260, S14X1261, S14A1262, S14A1263, S14X1264, S14A1265, S14A1266, S14X1267, S14A1268, S14A1269, S14X1270, S14A1271, S14X1272 affirmed in part, reversed in part and remanded with direction.

All the Justices concur.