Unfortuntately, the only entity that can modify your loan is your lender. They are not required to do so. And even more unfortunately, if you are making all the payments, and keeping you credit in good shape - they have no REASON to modify. Modification means they lose money. They only do that if they are afraid that they will lose MORE money if they foreclose . . . so you might not hit their radar until you are behind. I know that is a cruddy thing to say, but I see it all the time.
Visit the forum below and look for specific strategies that worked for borrowers that have the same lender. It may make sense to contact a REPUTABLE (GET REFERENCES!!!!!) Attorney in your area that has experience in loan modification to see if it is worth trying again.
Hundreds upon hundreds have posted their own stories here: http://www.loansafe.org/forum/
Unfortunately, though, if the lender doesnt modify, you have two choices . . . pay the loan, or stop paying the loan and allow your credit to be blemished. Technically, you are on the hook for the loan as long as you agreed to originally pay it.
Sorry, wish I had better news.