Vodacom Upgrades Contract without concent

Vodacom (Dial Direct) phoned on 24 February 2020 to offer an upgrade on a data contract. We did not accept the offer and asked the caller to first send everything via email. She took the mail address and told us that if we were satisfied with the deal, we could reply to an sms sent to my husband’s phone number - WHICH WE NEVER DID BECAUSE WE WANTED TO DO THE UPGRADE AT A VODACOM STORE. When I enquired today at the store, they told me that this contract was upgraded on 24/02/2020 via dial direct. This is the second time this happens to a vodacom contract !!!!!! How can Vodacom tolerate such ***** ??!!! I am very unhappy and will definitely take the matter further if vodacom does not supply proof of concent OR reverse the transaction asap !