MTN&Debt Collectors Failing to Clear My Name after paying up

I am extremely frustrated with the poor service I have received from MTN and their appointed debt collectors, NuDebt and Ludet.
My MTN account was handed over for collection, and I have since paid the full outstanding amount. I was issued with a paid-up letter, confirming that my account has been settled. However, my name is still listed as suspended/blacklisted, and I am unable to proceed with anything that requires a clear credit record.
For the past few months, I have been trying to resolve this issue with no success:
MTN keeps referring me to their legal department
The legal department does not assist and redirects me elsewhere
I contacted the debt collectors, but they are also not helping
I have sent multiple emails (over 10 days ago) and received no response
When I call, I am sent from one number to another with no resolution
MTN also referred me to log a dispute through VCCB, but when I submitted my dispute, I was told they cannot assist because MTN has not yet cleared my name on their system.
This clearly shows a complete breakdown in communication between MTN and their debt collectors, leaving me stuck even after doing my part.
I have fulfilled my obligation by paying the account, but MTN and their partners are failing to:
Provide a clearance letter
Update my credit profile
Remove my name from the blacklist
I request urgent intervention to:
Issue my clearance letter immediately
Update my credit record without further delay
Remove any negative listing against my name
I have attached proof of payment and the paid-up letter. This matter has gone on for too long and needs urgent resolution