Your aunt is not liable for the debt. If, for whatever reason, she failed to produce the necessary documents 5 years ago, you could have sought a court order at that time to compel her to produce those documents. Instead, knowing that you were not getting the necessary financial aid, you still enrolled and registered for classes, and by doing so you accepted the tuition charged by the school. You are also unclear whether this is now a debt that is owed directly to the school, or whether you took out a student loan that is now owed to a third party. If you took out a student loan, then you signed the necessary promissory notes, further showing that you understood the charges.
