I am sure the insurance company for the store has NOT admitted any liability. They always assign a claim number to any person wanting to make a claim, as that is how they track and look up each individual open claim. I have no idea what you mean by "an unmarked step" -- either the step represents an unreasonable risk of danger to the business invitees of this establishment and is not an open and obvious condition that an ordinarily prudent person would see and appreciate was there, or it is just a step. If the step is otherwise in compliance with building code in height and depth (not ADA compliant), then you may have a very hard time proving liability. Assuming for the sake of argument that the step is not ADA compliant, Maryland only recognizes tort liability for violation of a safety statute if the person injured was among the class of persons the statute was designed to benefit. You admit you are not disabled, so you would not be among that class of persons to whom the ADA provisions apply. regardless, your facts do not explain how the step is not ADA compliant, and furthermore, the Court of Appeals of Maryland has not yet spoken on whether a violation of the ADA, which is also the cause of an injury, is the sort of statute that gives rise to tort liability solely by reason of the violation. Cases in other states are split on this issue, although an argument can be made under existing Maryland case law. You would need an ADA expert to testify regarding that issue, which is not a cheap method of proof. I do not believe you have a good basis to sue the locker company, so I would focus your claim, if you have one, against the store owner and landlord/owner of the property the store rents from. Take multiple photos of the step, the entrance going in and looking out where the step is located, close up and further back in both directions, showing your point of view both in entering the store and leaving. if you can, take a ruler and stand it up at the base of the step and photograph it to show the height of the step, and do the same for the depth. Show the photos to a lawyer, together with all your medical bills and any doctors notes you have.

I do not know what an unmarked step drop is. You may be contributorily negligent. But you should talk to an attorney who will flush out the facts to see if you have a case.