ECMC - Educational Credit Management Corporation Ripping me off with absurd interest rates and ignoring money paid St. Paul Minnesota

In 1985 I got my first student loan. That loan was for 2500 dollars. I got another loan for the next year but never used it. It was still used by the school and I was told I had to pay for it. After about 20 years of interest bringing the money owed to about 10,000 dollars, my fight with the student loan people paid off, I got enough proof to show them I had never used the money and they wiped the entire debt clean except for the original 2500 dollars. I started paying on it. I had paid over a thousand dollars and ECMC took control and those payments vanished into what they called "interest". I have been unemployed since 2006 and have told them, but I've still been sending them money. The amount keeps going up. They now say I owe them $3215.17. I refuse to give them another cent. I'd be more than happy to participate in a class action lawsuit against these people. They are thieves.