I think you are going to have a hard time proving you didn't sign them because you already started making payments. You should probably have questioned them prior to ever signing anything. One question is how long have you been making payments.

Being electronic, I don't see how you can prove that you DIDN'T sign them. Not remembering doing so doesn't mean that you didn't in the FAFSA process. It would be different if it were someone other than your parents. But if they paid for your schooling, it's going to be hard to prove that you don't owe this since you were the one to benefit from it.

I know many people who are confused on student loans and see them as "free money" until they have to be paid back. I am sorry your parents failed to communicate this to you, but don't really see how you are going to be able to prove a crime/fraud, etc. Are their names also on the loans?