Poor customer service

I was sold a data sim by Vodacom during June and, as is my right, I cancelled it within a week. I called the *** number and cancelled it on 21st June. I was still billed and have been trying to contact them ever since. The call centre number keeps diverting me to another department, I have emailed *** and informed them. I would like to this contract to be cancelled as I have requested within a week of my purchase and the amounts deducted since June to be refunded to me or credited to my account.