End of contract

I contacted mtn in november 2015. I was told to give one months notice in order to ensure my contract is cancelled. I spoke to a gentleman not sure the name. Who assured me after asking for confirmation that the contract will be cancelled for sure on expiry only see now 21st march after no activity that they suddenly credited my cellphone as they used to with the contract and i called and was told today the cancellation was never done, no explanation the person sounded like too bad but she will make sure its cancelled.<br> why does MTN do this to people? I want resolution and my account refunded if any debits occurred after december 2015