I need to be removed from credit bureau by MTN

I've been owing MTN a Sum of R5 000 and I've paid it and got a paid up letter directly from the store, they have been calling me even after hours demanding their money, I paid them and now when it's their time.to remove me from credit bureau they are slow to do that. I'm struggling to even buy anything on credit or even make a bank loan while I paid them, the 13th August 2025