Taxpayer filed MFJ in 2008. The account number listed was for the spouse. In 2009, taxpayer got divorced and filed as single. The 2009 return was filed; however the account information was not changed and was still for the ex-wife's account. The return was rejected because of disallowance of the home-buyer's credit. Taxpayer paid the balance due after the rejection. An amended return was then filed for the credit and approved; however, the refund was direct deposited rather than a paper check issued. IRS claims a math error was made on the original return; therefore, they could direct deposit rather than issue a paper check. Ex-wife is balking at returning the refund to taxpayer. What recourse does he have?