Please I paid, give me my settlement letter

Terrible service I even think they might be con artist. I was contacted by revco in the month of June 2021, requesting I pay me FNB revolving credit account. I had been retrenched and my provident fund had just paid out. They advised that if I paid the same day they would give me a discounted rate and my debt would be sorted out. They gave me an amount and I paid it the same day. 10 June 2021, I have the bank statement to prove it. Thinking I did the right thing and that my problem was sorted out I forgot all about it. When I had the opportunity to buy a house the bank checked my credit score just to find out that FNB has been charging my fnb account which I don't use anymore. For this reason there are return debits from June up until now. Killing my chances at a home loan. I then contacted Revco requesting my settlement letter by phone and email. and to this day, I have no response. My credit score in now in the toilet because of what Revco didn't do and I am just not getting any response from the company, how is this possible. They are playing with my life