DEAR HARRY: Several years ago, I co-signed a loan for my son through Sallie Mae, the student-loan corporation. Shortly afterward, he stopped all contact with us and stopped paying on the loan. Naturally, they came after me for payment. Fortunately, I was able to resolve this problem by entering into a co-borrower release agreement with Sallie Mae in February 2009.

Since then, I have been contacted from time to time by collection agencies claiming to represent Sallie Mae. They insist that I still owe the full remaining principal on the loan. I have told the collectors and Sallie Mae to back off because of my agreement. That does it for while, but they keep coming back. I finally got to a supervisor, who asked that I email a copy of my agreement. I did it by email and U.S. mail. Last week, I got a call from this supervisor asking why I didn't send that copy. At this point, on top of all else, I'm starting to worry about my credit report. Help!

WHAT HARRY SAYS: What a nasty mess. This all started because someone at Sallie Mae pushed the wrong buttons. Re-send that copy by email. If that doesn't do the trick, you'll need a voice more powerful than your own. Get your congressman on your side. A letter or call can have a strong effect, especially where federal rules are involved.