Mortgage: Trouble during payment process

I recently refinanced my home and have been having trouble with the originating mortgage company PHH Mortgage, providing accurate information regarding my loan payoff. I initiated this request on XX/XX/XXXX & barely received a payoff quote on XX/XX/XXXX. Aside from the runaround I received in getting an accurate quote due to a 'shared appreciation ' amount they said I owed due to a loan modification done in XXXX ( I also think there should be a limit as to when they can try to recoup any increase in property value ), they have now come back and said the quote was inaccurate & I owed an extra {$1000.00} for the cost of the appraisal they ordered, although the line item only states 'recoverable balance '. Several issues here, I was not told that I would have to pay for the appraisal when I initiated the request. I now have a copy of a letter they said was mailed to me, but was not received by me vial USPS, saying I could order the appraisal or valuation, or they would. I only received a call from an appraiser to do the work, which I assumed was just part of their process, again, not being in receipt of the original letter. Otherwise, I would have ordered my own appraisal. The letter also states that if the mortgage company orders the appraisal, I would have to pay for it and the cost would be 'up to {$520.00} '. I have also called to ask for a copy of the appraisal invoice and the mortgage company 'ca n't find it ' and said they would have to do research to locate it and send it to me. So, they are trying to charge me over the amount stated, they can't provide proof of the amount charged by the appraiser, and they are threatening to return funds for the original payoff until the full balance is paid. I believe this company to be deceitful in trying to gain more funds from me when they can't provide sufficient evidence. They are also attempting to gain more funds by returning the payoff monies, they can then start to charge additional interest. Aside from the additional money being requested, I have 12 different payoff letters from the company, most in different amounts, and so they can't even figure out how much the payoff is in the first place. I'm refusing to pay any additional balances and request this company be investigated.