Account blocked. What account? No upgrade for me

Until about 2 years ago, I liked and recommended MTN to everyone. Now, I won't. I paid every cent I owed them early last year. Until recently, I've been speaking to agents at MTN Call centres and MTN Legal department who said my branch has to request support team to remove the notification from my profile stating "Account is at Legal" or something. What account? I don't even have the MTN nr anymore. I have emailed the Proof of payment letter to people at MTN. Nothing helps. I can't upgrade because of this. Well, no thumbs up to MTN from me anymore.