So pissed

So I got a letter from RSC.  I was wondering why they would send me a letter now since I am not cycling and I have paid all my bills.  Anyways there say that I have an outstanding balance of $577.12 and I can't cycle until I paid it.  Now I am really pissed.  I received 2 bills from them.  One for $625 and one for $188.59.  Both bills have been paid with my credit card and I have the credit card balance to prove it.  My $2000 deducible was reached by February and my 2 ER were covered in full by the insurance since our deducible had been met.  I have spent the past 30 minutes looking over my insurance claims online and I can't see anywhere where they are getting this $500 figure.  I come up with a $813.59 as how much I owe them and if you add up my 2 payments that is what that equals to.  Of course they send this on a Friday and likely the woman will not be in until Monday and I am out all day on Monday doing my fingerprints.  I am so pissed that I have to deal with this crap.  We pay good money for insurance and still have to pay a high deducible and then to get a letter like this saying we owe more money which is BS!
And then to prevent me from cycling because of a bogus balance I am beyond livid and so upset that I can't speak to them today about this!