DEEPLY FRUSTRATED AND ABUSED

Hi. I have been trying to cancel my data contract with Cell C for three months now without success. Cell C received my contract cancellation request but nothing is done so far. I have been calling them ever since but what i hear from you is nothing but empty promises. My contract was supposed to be ending since September. Despite my complaints and deep frustrations expressed, Cell C keeps on ignoring my cancellation requests and continues to billing me every month for the data i never use, and worst, they take from my account the double of what used to be the instalment amount. Last month I requested a refund several times unfortunately they keep on debiting from my account R1559 (which is the double of what the expired installments). I call this an abuse. I am deeply frustrated. Please advise on the way forward... I took on Facebook and Tweeter in the hope to have this sorted quickly but no success so far.