What is your question? Are you being sued civilly? If so, by whom?
If the check cashing place gave you the funds and is coming after you, it means that the check casher may not be able to find the maker of the check.
I have not researched this, but this might be something which falls within the 6 year statute of limitations. If not, it might be 4 years in which case the statute would have expired.
My suggestion would be to take the summons & complaint to a consumer defense lawyer in Georgia and allow him or her to review. If the statute of limitations has expired, then you need to pay the attorney to draft a proper answer for you and get this dismissed.
If the statute of limitations has not expired - it may depend on what you want to do. If you want to litigate, I would file an answer and include a cross-claim against the maker of the check who gave you the bad check to begin with. That is the person who is ultimately going to be liable.
If the person who made the check truly cannot be found, you are the one who got the money and as between you and the check casher you might be liable.
The company that is collecting for the check cashing location, if they are a third party debt collector, are subject to the Federal Fair Debt Collection Practices Act. Save any calls and record any messages that they leave for you. Specif things to look for are threats of prosecution, which may not be appropriate here. Also, there may be disclosure violations in their letters or calls. If they violate the FDPCA you may be entitled to statutory damages of $1,000.00. We are in the metro area if you would like to discuss this, feel free to check out the law on our website or you may call me directly at 404-373-1970. Good Luck.