Philmont Guidance Center

I received a collection letter today from *** for Philmont Guidance Center for $$503.23. The letter says I was contacted in the last two weeks- I was not. My last communication from Philmont was Oct. 1, 2019 in form of a statement for $463.33. I had just made a payment of over $500 to them. I tried calling many time with no answer and no call back. Items on the Oct 1 statement are from 2017 I never receive regular statements or bills. When do get statements there is no itemization of payments from ***, Medicare, or me. There is no rhyme or reason to how I am billed. I want a an itemized statement showing all Services, insurance and Medicare payments and adjusted, and my payments. As of now I have no way of knowing I actually owe this money I had been previously been told that the billing office had issues. I had to tell them several times that *** was primary and Medicare secondary.