On an a normal 30 year loan - fixed or adjustable- you only pay your principle and interest one month at a time per an amortization schedule. So other than your last "early" payment, what would you be owed a credit for?
Did you pay your taxes early? Doesn't matter-you still owe them. Your escrow account includes insurance? Call your insurance carrier. Didn't you get a "final payoff balance" when you paid the last payment? If you added your last current payment to your principle balance at that time, I can't see why there would be any credit owed there. Anyway-ask for a final statement of payments-and your signed off deed--from your lender. Congratulations! Time for "burn your mortgage" party!
I agree with austinlinda. What would you be owed a credit for?? When the loan is originated or closed, the bank determines exactly how much it will take to pay the note monthly over 30 years (including accrued interest). If you paid more than the monthly payment each month or lump sum(s), it just means that the interest that would have been charged during those 15 years now no longer applies. Did you accidentally pay them too much - as in, more than the note? If not, then I can't imagine where a credit would come from.