pathetic cancellation of contract

my contract with MTN expired and it seems i cant cancel it even though i dont owe them a cent, every time i call to know the status of my contract cancellation i get told different stories like..my request was not logged, it takes 2 to 5 days to cancel the contract, it takes 30 days to cancel the contract, i told them not to load any airtime or data as i dont want to be on contract any more, but they still do load it and tell me i am going to be billed for it even though my contract expired. i am never signing up contract with MTN if this the pain you have to got through to cancel a contract that has expired already..now it has been 10 days trying to cancel my contract without any success..my brother was able to cancel his contract with 2 days.he ddnt get all this pathetic stories i being told everyday..why is my case being treated differently