I made the mistake of borrowing money from a friend.

The first thing I would need to know is whether the loan was memorialized in writing. In other words, did you enter into a contract or some sort of promissory note with her that you both signed? I ask that question because if there is not one, then it is up to her prove the existence of the note/contract and balance owed if she sues you. At that point you could also find out through discovery whether she accounted for any payment offsets. If she did not keep records of payments then it could make it hard for her as well. As for your recourse, it is an affirmative defense to suit on a note that it has been paid plus you can always claim the offset if she sues. With all that being said, I suggest you send a simple professional letter to her simply requesting a payoff amount. I hope this helps.

Of course I must state that no attorney client relationship has formed at this time. If you need further help, I suggest you contact an attorney.