Kim
I would suggest calling them back, and getting that in writing. You need to protect yourself, because at some point they could attempt to hit your account again (if you haven't already changed your account number).
Also, if you get taken to Judge Judy (for instance), she'll ask you "did you get it writing", and since you had an agreement with the lendor, the ball will be in their court, if you can't prove everything was paid/cleared.
Regards-
Mike