Product: Mortgage

There are numerous issues I have had with this Carrington Mortgage Services , LLC . First, my loan was with XXXX, and was not due until the XXXX of each month, and when they " took it over '' it became the XXXX. I was never asked, it was simply transferred without my consent. While this in itself is minor overall, one of their third-party associates, XXXX, apparently let my information get leaked out ... and yet they still want everyone to use their online payment method. 
I have been using checks fro quite a while, successfully, until about XXXX of XXXX when one disappeared. I have had another check disappear within the last few days, again going to Carrington. And there have been a few other cases where it showed up several weeks later, but at least the checks did show up. While I have not completely eliminated XXXX from contributing to some delay in delivery of my payments, the fact that I have sent other checks out at the same time to the same USPS on those dates, that did get tot he destination in a reasonable time, this would seem to clear the USPS delivery process. And, this seems to only happen to checks I mail to Carrington. 
You may be asking why I don't use their online service? How can I trust their online services when they have already allowed my information to be leaked?

Not only that, one security step they have added, that is completely bogus to put it mildly, is that the automated system will ask me for the last 4 digits of my SSN, which they have been doing for a while and is quite normal, they then ask my for the FIRST 4 digits of my SSN! Given the fact that the SSN only has 9 digits, and I have had to give them 8 digits, they would have a 10 percent chance of guessing my full SSN number right off the bat. How is this more secure??? It means they have access to all by one digit of my SSN, and given their leak earlier, is only a matter of time before my information is stolen or leaked again... perhaps by one of their own employees. Hopefully not, but it is now more likely that it would be if they only had access to my last 4 SSN digits. 
All of these payment issues not only affects my personal credit score, but also generates late fees and a fee every time I have to get my bank to cancel the check ( that appears to be lost ). I suspect, in one way or another, they are using a convenient mailing address trick to deliberately slow down the payment process to impose late fees on me ( and perhaps others ). This tactic needs to be stopped, and at the very least, they need to make sure that their billing department puts the correct, and most efficient and accurate address to send payment to instead of the one that several of their customer service reps. 
The payment stub has an address going to XXXX, CA that is apparently not current or an office they are trying to shut down. Yet, their website does not have this website listed. Too bad this is the address that has been on may payment stubs ( and thus the front of the envelops for me to mail to them for months, if not a year or more. ( I did not have problems until about XXXXXXXX XXXX XXXX that I know of, so perhaps that is when it changed. ) Even though they say over the phone that I should use the XXXX, TX address, they somehow never have it on the payment stub that functions as the address label for the bill payment stub. While a few of the reps I have talked to over the phone seem to share my concern, the others do not care.