Product: Mortgage

My mortgage was serviced by Primary Capital Mortgage from the time the loan was taken out in mid- XX/XX/XXXX ( 1st payment due XX/XX/XXXX ) through XX/XX/XXXX, at which time it was transferred to XXXX XXXX as of XX/XX/XXXX. 
I sent XXXX 's mortgage payment but it did not post ( I was not aware it did not post until I received a statement from Primary on XX/XX/XXXX showing that I was past due for the XXXX payment of {$1300.00} ). This statement, dated XX/XX/XXXX added a late fee for the missing XXXX payment and showed the amount to catch up XX/XX/XXXX and to also pay the XX/XX/XXXX payment, which totaled {$2700.00} ( with late fee ). I sent a payment for {$2700.00}, which cleared my bank on XX/XX/XXXX. At this point I should have shown as current on the loan. However, I began receiving late charges and statements saying I was past due 1 month. I didn't understand why, thinking maybe payments were crossing in the mail? 
When my mortgage was transferred to a different servicer, XXXX XXXX, and they also showed me as a month past due, I looked at my bank account to make sure all checks that had cleared had been posted to my loan account. I found all payments had cleared, including the check for {$2400.00}. However, when I reviewed my XX/XX/XXXX Primary Capital Mortgage Statement I found that they had applied only 1 payment to the account and the other payment amount included in the same check, went to " Principal Curtailment ''. Since the statement I was sent in XXXX showed me as past due, advised me the amount needed to bring the account current ( 2 payments- 1 for XXXX, the other for XXXX ) and I sent that amount, I was surprised to see that they put the second payment amount to principal ( when not directed to ), rather than applying both payments as they should have. If the check for 2 payments had been applied correctly this would have brought the account current. Instead, due to them putting the 2nd payment to principal, I have shown past due continuously for every month since their error, and have been charged for late fees for XXXX and XX/XX/XXXX from Primary Capital and now a late fee from XXXX for XXXX. Not only have I received 3 late fees to date due to their error ( the 1st one in XXXX is due to them not receiving the payment, so I am not including that one in the 3 ), this could be affecting my credit. I contacted XXXX on XX/XX/XXXX and was told since Primary had the loan prior to XX/XX/XXXX we needed to contact Primary. I contacted Primary on XX/XX/XXXX ( due to limited customer service hours, couldn't call sooner ) and they said since it was transferred the only thing I could do is send a written letter to their Research Department ( even though the representative could see what happened with the {$2400.00} check, and should have been able to reverse the principle payment and show it as a payment and reverse applicable late fees ). I later called back and spoke to a supervisor at Primary and she said there was nothing they could do since they transferred everything to XXXX. So, I called XXXX back and spoke to a supervisor there. She was helpful and said she would contact XXXX and see if they can move the payment amount from principle to show as a loan payment or allow XXXX to do this. Due to the run around and the change in servicing companies, I am afraid this could take some time for them to figure out. Regardless, it appears Primary is not applying payments as they should, resulting in late fees for myself ( possibly others? ).