Need Help

I posted last week about 8 CA listings on my report for medical bills. I called the Hospital directly and they told me they were paid. An attorney for the hospital had received the payments. I called the attorney and she called the CA, I guess she really gave them what for!
Today I receive a letter from the CA, I had sent them a letter giving them 5 business days to delete the accounts, or I would file suit. Anyhow, they sent this letter saying that they had 6 of the 8 removed. They claimed the other 2 accounts are not with the Hospital, but with a physical therapist. I know I have been paying the therapist each month for a year, he's almost paid off. It appears this therapist turned the account over to this CA, and when he receives the payment each month, he forwards the payment to this CA. Sounds screwy to me.
I thought I was finished with this CA! Guess not. In the letter they say when I pay the accounts they will list them as paid collection, they WILL NOT delete. I think they are ticked off because an attorney gave them a hard time on the other 6 accounts, and I sent a letter threatening a suit if they did not delete. What do you think? HA HA.
So I only owe $85.00 to the therapist, it goes directly to him first, then the CA. Do you think I would get away with slipping a restrictive endorsement on the check. Cash this and the account will be deleted kind of thing?
I live in NC. A&S is enforced. But is it legal for me to NOT include an A&S letter with the final payment, just restrictive endorsement on the check?
I don't think I can talk the CA into a deletion. Although they did violate several laws to begin with. No initial letter from them, never validated after my request, wrote the BBB(after I filed a complaint)and lied about sending a notice, and giving me validation on all 8 accounts. Any suggestions would be appreciated.