Upgraded my account without permission

Vodacom upgraded my account without permission. I contacted Vodacom in August to cancel my data contract with them. On the 26th of August I received a call from a consultant advising me that Vodacom can offer me a new data contract for a much lower price. I asked the consultant to send me a quote as I do not have time to check all the details and that he can contact me later. He sent me the quote, to which I did not reply as I did not want the contract. Today I found out that the contract was added to my name. NOWHERE did I consent to this! Not over the phone and not via email! I am not paying for the contract and Vodacom needs to take this off my name ASAP! YOU ARE NOT ALLOWED to do this and you do NOT have consent!