I app**** for paid-up letter

I was handed over by MTN to SSDA, I paid them on the 14th October 2024. When I phone SSDA I was informed that I must call MTN. I phoned them ,in an hours time after struggling to get assistance. I got the email address to request paid-up letter. I sent an email. No paid up letter and no feedback when I email them. 21 working days are up. I need to fix my life. When I phone MTN they keep on putting me through collections. I've been on phone the whole day. No assistance.