Need Advice for Old Student Loan Debt
As with all loans, the interest is paid first then principal. With defaults, you also have collection fees to as well. So what you owe is principal and interest. This is what you agreed to pay so yes, it is fair.
Your mom might have been a cosignor...but you are still the responsible party. They have no obligation to go after her if they are getting the funds from you.
FYI...you are not going to get an itemized statement of all your payments. Your loan would have originated as a FFELP loan. It is now in the hands of the Department of Ed. If you want record of the payments, you would have to request it from your individual holder. i.e...your original loan servicer, your FFELP garantor. Department of Ed would only have record of payments or offsets you made to them.