Product: Mortgage

In XX/XX/XXXX I logged onto the company website to submit my XXXX payment. I normally schedule these thru my bank. When I logged in, the amount showing due was double what it should have been. I checked the posted payments and noticed that they had not posted my XXXX payment ( the payment due XX/XX/XXXX ). I sent them a message thru their messaging section on their site and then, since I could not change the amount to pay on their site, I went ahead and scheduled the payment thru my bank. 
They replied to my XXXX message saying to send a copy of the check, but they didn't provide the " where '' so I sent another message in XXXX and requested an email address so I could send them a pdf of the front and back of the cleared check. No response. Due to a personal illness, I was late in getting my XXXX payment scheduled thru my bank, so I logged onto their site prior to XX/XX/XXXX to make the payment. It again displayed an amount double what it should have been and would not let me alter it. So I scheduled the XXXX payment thru my bank ( they sent it on XX/XX/XXXX ). 
I sent another message on XX/XX/XXXX when I noticed that the XXXX payment had not yet cleared my bank. I requested that someone contact me regarding my account but that did not happen. I thought about waiting before sending in the XXXX payment, but I don't like to be late. So instead, I stopped payment on the XXXX check and thru their website, on XX/XX/XXXX, I paid both XXXX and XXXX. I sent them another message on XX/XX/XXXX to this regard and notified them that I was stopping payment on the XXXX check that had not yet cleared. 
When I got to looking back thru the statements, and trying to figure out why they were suddenly having such a difficult time properly processing my payments, I noticed that they had changed my account number. The original account/loan number was XXXX. It was changed on the XXXX statement to XXXX. 
I called several times thru all of this, the last time I believe was in XXXX. The person I spoke to kept trying to tell me I was late but apparently could only access what I saw when logging in which did not show the XXXX payment. I asked if I could email him a copy of the cleared check, but that he couldn't do. So I told him I would get copies of all payments, front and back, of all the checks that had cleared my bank, beginning with the XX/XX/XXXX payment and thru the XX/XX/XXXX payment. Most of those were made thru my bank Bill Pay. Four were made thru their site. I sent a certified letter to the company on XX/XX/XXXX and included the printed copies from my bank of all the cleared checks, as well as the payments made thru the company site, along with a letter. 
I received a letter in XXXX from them stating that they couldn't make out the information provided from the copies from the bank. This just seemed another excuse by them. I could have sent screen shots of the cleared checks but expected they would want what the bank provided. 
The first week in XXXX, I received a notice that they were turning my mortgage over to a new servicer, and no payments should be sent to them after XX/XX/XXXX. My XXXX payment was sent to them prior to this date and has cleared my bank, but they do not show a XXXX statement and right now I don't know if the new servicer will show that payment or not. 
Today, XX/XX/XXXX, I received an email alert regarding my credit. When I logged in to check the report, it shows that this company has reported my account as delinquent and my score has dropped 77 points! I am NOT delinquent and I have been more than patient in working with them and providing the PROOF that all payments have been made. Talking to their agents did me no good and apparently neither did sending in the certified, written request with copies of the CLEARED CHECKS. Additionally, they have applied late fees to my account, totalling {$25.00}. I imagine that they have also transferred the wrong balance to the new company. 
I have had this account with them for years, and never had a problem until XXXX. By not properly recording my payment, and then not correcting it during the seven ( 7 ) months that I communicated with them, they have caused me a lot of time, grief, and frustration, and now, they have affected my credit! They ( them and companies like them ) should not be allowed to do this to anyone! 
My last name has changed but I have not submitted the paperwork to have it changed on their account.