Paid up letter

I am so disappointed with MTN as their loyal customer since 2008. On the 14th of September 2024 I paid off my account which was handed over to legal team. First of all I wasn't aware that I was owing MTN, no communication was made but that is for another day. My main problem is that MTN is not willing to give me a paid up letter, I phoned legal team they said they don't issue the paid up letter, I must ask from customer services, even with them I don't get assisted. I've been trying to get this letter since September, as I want my name to be cleared. I have so many problems with MTN and I don't think I will ever take any contracts with them.