Breach of Contract

I had a modem contract deal with Vodacom that expired January this year. Sometime in December I phoned their helpdesk to cancel the contract as it was coming to an end, which they said they did.<br> Vodacom still continue to debit my account even after I cancelled the contract, the worst part is that they debiting more money for the service that I have not been using since December. <br> As per the agent, the contract is cancelled and the number is a prepaid number now, she transferred my call to their Account-section(***) and I had to hold for more than 30 minutes and no one answered. I need this matter resolved ASAP as I can't continue paying for a service I don't have.<br> <br>