Product: Mortgage

I recently refinanced my loan and already into the first month of servicing with Carrington Mortgage Services , LLC, I'm already having issues with them. 
Do date, I've sent 2 Principal Reduction Payments and both times they have misapplied, and misposted my payments for principal reduction. 
The first mishap was XXXX ; they applied my PR check as a mtg payment, I contacted them and they said they will reverse it and apply it as PR within 3 days. 3 days turned into almost 3 weeks. They finally applied the PR as I intended on XXXX to show a loan balance of XXXX. During this time frame, I probably called 3 times to follow up and the last time I called to follow up they said it would take about 3 weeks, not 3 days to be corrected, but 3 weeks when my check was clearly marked as Principal Reduction. 
During this time frame, I did not make my mortgage payment since I have a grace period until the XXXX ; because I wanted my payment to be applied towards the correct Principal Loan Balance. 
Also during this time frame, I was able to make a Second Principal Reduction check which Carrington received on XXXX. They said in order for me to avoid having to call and follow up on Principal Reduction payments, I would need to send it to their XXXX, CA address since they handle PRs directly. I did this, and to my surprise, my principal Reduction check was cashed and cleared but NEVER posted or misposted. I called after the 4th business day of them receiving my check onXX/XX/XXXX and they said the check is an a suspense account. The amount does not reflect in a suspense account on my online account. They also said I can not make a Principal Reduction payment until they process my mortgage payment because I have to follow FHA Payment Guidelines. I let them know that my loan is NOT an FHA loan and my indication for the payment was to be applied as a principal reduction. Carrington refused to correct and post the {$1000.00} Principal reduction to my account. They insisted that I am subject to FHA regulations for posting of my payment and said I'm subject to a payment Hierarchy stipulation where if a payment is due, I can not make any principal reduction payments. I asked for them to tell me when was this disclosed to me and they were not able to give me an answer but that I can order that disclosure and it can be mailed to me. As far as I am concerned, my contractual agreement with the Lender is my Note, and in my Note, it indicates I can make principal reduction payments and I have a grace period of making monthly mortgage payments by the XXXX of each month. In my opinion, If am able to make principal reduction payments, then there should be no concern that I am able to make mortgage payments. 

So far, I've made 2 Principal reduction payments and both have been misposted and misapplied. I am very concerned for other homeowners that make these principal reduction payments and their funds are being misapplied as their intentions indicate on the payment that Carrington is  receiving. 
To date, my account is still not reflecting the correct principal loan balance that should be XXXX, of which my XXXX payment should be deducted from. Carrington does not have good servicing practices and every time I talk to a Customer Service rep, their so called " policies '' are turn around times are different.