MTN bad service.

I have had a contract with MTN for over 20 years. At the end of November when I receive my normal allocation for the following month, without any notification they took my data away that's written in the contract.On querying they were unable to help with any kind of explanation except that it would be escalated. One would think that it would be a simple matter to just correct the mistake by the push of a button or do they need to discuss it first and formulate a plan of action going forward. Excuse the sarcasm but this is ridiculous.