Poor client service

I.settled my account with Mtn September 2024 then I received a paid up letter after payment then I submit the letter to experian for update of my status but still I'm on credit bereu even today.Yesterday I called experian to ask them to update my status then they promised to remove my name before the end of the businesses day nothing changed so today I called Mtn they told me to for 60 days can please somebody assist me please