Paid up letter

I app**** for a sim only deal last year and the consultant explained I will be able to do a sim swap. Upon receiving the sim I couldn't do a sim card because they said it was registered under Unisa students. Cool, I don't use the the sim, montgs later the account is handed over and I was told I need to pay for the services I didn't use. I SETTLE the account in January. I have been calling for the past 3 months requesting a paid up letter which I am being told I'll get after 48 hours. Till today none has been issued. My credit profile still shows the account as not been paid.