Cancellation of Vodacom contract

I have been struggling for the last three months to cancel a contract that was due for an upgrade. Every month Vodacom confirms the cancellation, but at the end of the month we still get charged for the contract. My second last call to your offices was on 30 June, again it was confirmed that the contract was cancelled. However, yesterday I found that we are still being charged. I phoned now, and low and behold, the contract is still active. We are very good customers, having a total of 7 contracts with Vodacom. I expect better service. Now waiting for a team leader to phone me back. I am not holding my breath though.....