Canceling a contract is a nightmare

Canceling a contract is a nightmare. The contract of My10gig for R 359p/m with you ended on the 6th of October and I have been paying you without skipping any payment since. I canceled this contract with you on the 9th October and got confirmation that your staff has received my email and it's been escalated to the cancelation department. Only for my account to be credited with 15GB on the next week and immidiately I sent an email to tell you to take back your data because I don't need it and I can't afford to pay for it as I can't afford to pay for anything at this point but still today there is no response. To my surprise today I received an invoice saying I owe you R 969.00 of which I do not know what this is for. And no 15gb data will cost R 969.00 unless only with MTN. Please MTN I am still waiting for you to take back your data. I didn't request for it and I do not have money to pay for it.