Bad service

I have an account with MTN that was handed over to attorneys, I therefore wrote on the MTN page on Facebook (inbox )to give me the attorney’s number which they gave me VVM . Upon contacting VVM they told me they no longer work with MTN and my account is with SHAPIRO SHAIK DEFRIES. I contacted them and they gave me a settlement letter R7409,93 which I paid . I therefore requested a paid up letter and they told me they sent letter to MTN for the paid up letter ✉️, it’s been weeks without it . I am now being harassed by other attorneys calling themselves Saya Recoveries . According to my knowledge when you are given a settlement letter and pay 💰 you are done with the debt and you must get a paid up letter ✉️. All I’m asking is a paid up letter and these Saya people to stop calling me