MTN slow and *****ing my money

Got wrong information from MTN sales person in Vaal Mall MTN store when I signed a new data contract and because of the wrong information given I lodged a cancellation within 7 days. It is now 3 months and still not cancelled. Best is I have not used 1Kb of the data and MTN already took R2500 and seems it will still continue. It just seems impossible to try and cancel it. PLEASE DO NOT USE MTN I BEG YOU!!!!!!