in 2001 i obtain a federal student loan for my son, i was always on time with the payments; in an unsolicited e-mail "I did not respond to" great lakes co. paid off the loan and is now asking me to pay them instead, 1. I did not sign any thing requesting a pay off 2. my ex husband was ordered in divorce judgement to make the payments way before the e-mailed me. What are my obligations to pay?