How can it be so impossible to cancel a contract at vodacom

Good day. I canceled my contract with vodacom in January but to my surprise they billed me for my canceled contract as well as my upgrade. When I phoned they advised me that they will listen to the voice recording to confirm that my contract was canceled and refund me. Later in the week I received a sms saying that if I don't receive a sms to confirm cancelation than the contract was not canceled. When you ask who to complain no one can give you the complaints process. Eventually receive an email address *** but no response so far. Went to vodacom shop in Baywest yesterday and wanted to see if they can assist to get this sorted, I was told that they cannot do anything because it was done online. Really this is the worst service ever. Not to mention the second time that vodacom is doing this to me. Just so disappointed if I could get out of this upgrade I would but now I am stuck....