MTN month to month contract is a disaster.

Good morning, on 31 July I cancelled a month to month contract and on the 1 of August I returned the MTN router and accessories at Bayside Mall MTN a monthly later I discovered that the cancellation was not done just because I got a bill for August month then I returned to the store for a follow up. The lady who initially assisted me told me that the cancellation was done and forward the router and accessories to MTN Head Office. Till to date I am getting bills and I have been calling MTN call centre without getting assistance and I am told that my account is handed over to MTN legal department. I even informed MTN Ombudsman concerning this matter but I never got response from them.