If you saved the paperwork, you can sleep tight

Your old lender must provide you with a loan ownership transfer notice when your mortgage is sold. The new owner of your loan must notify you within 30 days of the effective date of transfer. Included in this notice should be the following information: the new owner's name, address and telephone number (and if different, the person who can resolve issues concerning your loan payments or any right to rescind the loan), the date of transfer, and whether the transfer of ownership is recorded in public records.