My mortgage coupon book states that my mortgage payment is due on the 1st of the month, and is considered late and late fees apply after the 16th of the month. I made my April payment on the 14th, and have proof of my payment. I got a letter from the mortgage company on the 16th telling me that my payment was due on the 1st and I now owe late fees and this will be reported to the credit bureaus and be reported as a negative against my mortgage payment history. Is my mortgage company correct and can they do this?