VODACOM REFUSES TO PAY BACK MONEY OWED TO ME!!!

I previously had a data contract with Vodacom which was CANCELLED In time as per THEIR instruction. Following me officially cancelling the contract they continued to debit my account for another 2 months. I’ve been trying to get my money back for almost 3 months and they send me in circles all the time talking about “escalations” but they escalate and SOLVE NOTHING. I am so frustrating with the thieving strategy. It’s almost like they want me to forget that they owe me almost R2000. Kindly help me get attention. I’ve called them more than 20 times. I’m constantly in distress and they are causing a serious amount of stress to me. Please help!