Product: Debt collection

I owed Medicredit a medical debt of {$2900.00} that they purchase from XXXX XXXX XXXX XXXX XXXX XXXX XXXX ) after a XXXX back in XXXX. I never saw a bill come from XXXX XXXX, so how this account when to collections in the first place is beyond me. I received other bills from the hospital and got those paid but never received this bill. I called Medicredit on XX/XX/XXXX and spoke to a XXXX. After negotiation, she agreed to settle the debt for {$2000.00}. I asked them if I settled the debt, would the balance on my account show {$0.00} and the remaining balance of {$890.00} be written off and XXXX said yes. XXXX told me how to go onto their online portal and pay the debt so I did. The amount still showed the full {$2900.00} and she told me to manually enter the amount we agreed on which was {$2000.00}. I then asked her again if I manually enter the amount, with the remaining balance be written off and XXXX said yes. I then called back and spoke to XXXX and asked the exact same question and XXXX said yes as well. I asked for a payoff statement and they said they will mail it to me and I never received it. I paid the {$2000.00} in the portal with my XXXX card on XX/XX/XXXX and the payment posted to my credit card account on XX/XX/XXXX. I attached a picture of the receipt from the portal and a screenshot of my credit card showing the posted payment. I then called Medicredit again on XX/XX/XXXX and spoke to XXXX and expressed to her that in the portal it still shows I owed a balance of {$890.00} and I wanted to confirm this amount would be written off and I would be receiving a letter of payoff. XXXX said that usually the payment would be shown in full but she can see that there was still a balance. She put me on hold and then came back and said the payment had just posted and it would take a few days for it to show {$0.00}. I went back in a few days later and the balance still showed {$890.00}. XXXX said the letter would be mailed to me within 10 business days and I still never received it to this day ( XX/XX/XXXX ). I have almost every conversation with Medicredit recorded in voice memos on my phone and I am willing to provide these recordings. Now I am receiving a call from XXXX debt collector trying to collect on the remaining balance of {$890.00}. There is no reason at this point ( 2 years later ) I have a new collections agency trying to collect on this amount. I called Medicredit today, XX/XX/XXXX, and talked to XXXX. I asked her to speak to a manager and told her why I was calling. She tried to page he manager, XXXX, but he was busy and will call me back. He has yet to call me back 2 hours later. I have the conversation with XXXX recorded as well. I called XXXX XXXX and spoke with XXXX. I explained the situation and she said the bill would have went to an address that I only lived at for 2 months over 5 years ago. The XXXX was in XXXX and I moved from that address in XXXX. Not sure how they had that address. She sent an email to the analysis team while I was on the phone, explaining my situation and they said they would reach out to MediCredit to see what I was saying was true. I told her that I had a printed statement from the MediCredit portal showing that the agreement price to pay was {$2000.00} and was willing to provide this if necessary. XXXX said I can call back as early as Monday ( XX/XX/XXXX ) to follow up with my claim.