Product: Mortgage

I bought a 4 bedrooms townhouse XX/XX/XXXX. There is a primary borrower and I am co-borrower through XXXX XXXX.We like XXXX advertisement that they are good to the customers But, XX/XX/XXXX, XXXX XXXX sold the service to XXXX XXXX XXXX. XXXX  toast us out the window. XXXX  charging us for taking payment over the phone which was free with XXXX XXXX. To avoid the payment I mailed in my check XXXX claimed the payment was late charged me penalty. I complained to XXXX about it. 
XX/XX/XXXX Fay Servicing purchased my loan from XXXX XXXX. They said then I have a XXXX allowance after the payment due date because of the completion of the paper works transfer there will be no charge when I pay later when the transfer is completed but they lied they charged me a penalty. They told me no charge for phone payment. I paid them on time except last XX/XX/XXXX they claimed my bank refused my payment. 
I asked the manager of my bank about the money. He told me no one tries to withdraw {$800.00} in that month of XX/XX/XXXX. I called them again XX/XX/XXXX I gave them and confirmed the account number again, by XX/XX/XXXX I think, I got a call telling me the XXXX they sent to my bank was return firstly, I only have XXXX in my account because I owe them XXXX. They are not authorized to take the full amount I only owe 50 %. off the loan. I asked for the bank account numbers there were 4 extra numbers in it. It was the wrong account number. Then, I was told I will have to pay XXXX for phone payment. I was told to mail a check. But, I know they will say your check was late so will charge me XXXX penalties. 
I use bill pay I went to the bank they set it up for me and send the check. In my online banking, it showed they got it on XX/XX/XXXX and XX/XX/XXXX. They called me yesterday in the afternoon XX/XX/XXXX they only got the XXXX check they can't give me anything ref. Numbers etc. I called again tonight I was told that I have to go to my bank to get a copy of the cashed check so, they can trace the check which accounts it was deposited maybe the other checks was deposited to another account that is not mine. 
I have to waste my time to prove to them I paid them for their negligence in the meantime I am out of XXXX. I believe they are using a dirty tactic of business so they can charge me a late fee they lied in their online advertisement.Welcome to Fay Servicing! 
Fay Servicing is a specialty mortgage service and originator that sees the customer behind every loan. At Fay Servicing, we understand that you are not a loan number you are a homeowner. 

When I called to ask questions they do not answer me they can't answer anything we can't just give money without any confirmation information on payment. They cause me stress to try to prove my payment I have responsibility to pay my due their responsibility not to bully me. I waste too much time on their mistakes and turn around and blame me. I called the mortgage manager as suggested and leave a message to call me back last night but, he doesn't call me. I called my bank this afternoon to asked about my check payment to them They cashed one check XXXX XXXX XXXX CK # XXXX XXXX this was for XX/XX/XXXX. Payment. The second Check XXXX suppose to arrive XXXX XXXX is not cash yet. I called Fay servicing this afternoon it seems no one can answer anything. What kind of business they do? They are the worst people I ever dealt with. I think they trying to give me trouble so they can foreclose the house.I was told again to call my mortgage manager that never answer the phone XXXX XXXX XXXX I left him another message to call me, again he never call me back. now it sounds like I am two months behind XX/XX/XXXXand XX/XX/XXXXthese people I think are lairs. 
When I logged in online I can't see the payment of which bank account numbers I see like when we were with XXXX XXXX I wish XXXX  did not sell the service to another company. If they can't handle a lot of clients then stop taking clients. 
Help! I work every day I don't have time dealing with them they are rude. 
I want to keep my house they already send me penalty letter.They also give me 45 days warning letter in the site messaged but is gone now I can't attach a copy.