First call your lender and see who you would need to contact. Sometimes the companies that service your payments are not the ones who can help in this matter. They may be able to amend your payments temporarily until you are back on your feet. You would send the letter by certified mail to make sure it is received. Alternatively, you might try to sell the house if you can get the amount of your loan for it, only if you are not currently behind. This would protect your credit history.