I started to use my Bank of America online bill pay they keep there address up to date as well as ASC CAN NOT FIGHT B OF A over payments, the bank will not let someone say they did not get a payment when the bank its self sent it and I have not had any more trouble with them as well as I have had late fees reimburse so there is a small but very useful bit of advice no more keeping trake of where to send the payment and no more late fees so long as it is sent in on time!

As for your loan getting sold there is no way you can stop it. It is a commodity to be bought and sold like any stock or gold and silver. Also this should help in the event that your loan is sold the bank will trace the payment down and with this information you should be able to get the new holder to credit your account or get ASC to send it to the new holder because not all loans fall on the same day of the month some payments maybe prorated as to the day the new holder receives owner ship.
Here is a link to the sign on page for ASC

WWW.MORTAGEACCOUNTONLINE.COM
this number give the web address if i have miss spealed 1-800-662-5014

Create an account and Please always do your best to keep your loan in good standing and thou i had a lot of trouble with them in the past they did not cause all of it

Thanks
Danny