MTN service delivery is putrid

I recently had an account with MTN which was in arrears and handed over to the credit bureau. I have since paid the arrears in full in March since then I have been trying to get hold of the legal department to get a paid up letter so I can remove the blacklisting on my name. Whenever I call they say they’re going to transfer me and they can’t even get that right . I have sent numerous email with my zero balance sheet as proof attached , when am I going to be assisted???