Poor MTN service

I have been in contact with MTN for nearly 2 months now regarding my account which to my knowledge I cancelled. I was handed over and I made contact with the service provider (MTN) on numerous occasions. I spoke to 2 agents at MTN call centre and both mentioned to me that there isn’t an outstanding amount in my account, all I require is a settlement letter so I can clear my name. I’ve sent numerous mails to MTN (***) and to date I have received no response yet. I would never advise anyone to take MTN services again because their after service is poor.