Billing a cancelled Contract

Hi<br> <br> After months of struggling to cancel my contract with MTN, I only got help when I complained on Hello Peter.<br> <br> Now after moving me to Prepaid, they have debited my account again. I don't owe anything. <br> Everytime I call the call centre I get transfered to Pay as you go but they can't help and the contract call centre can't help because my number is no longer a contract number. <br> <br> How does a person get good service at MTN?<br>