Vodacom Upgraded my contact without my consent !!!

On the 31st of January 2020 I received a call from a Vodacom rep while I was driving, as the guy introduced himself over the phone I told him to call me back in 20minutes,(which he didn't do) ... A few days later I saw a message via SMS telling me I have been upgraded to a uChoose Flexi 65 Plan & giving me my new upgrade date being March 2022 - I have been trying to get ahold of Vodacom since 3/4 January 2020 to cancel this upgrade as it was done without my consent !!! I knew I was up for upgrade but I didn't request to upgrade as yet but Vodacom upgraded me without my consent !!! When I spoke to a Vodacom consultant requesting a cancellation , I was told I will pay a cancellation fee of R1000 something .. How am I liable to pay a cancellation fee of an upgrade I didn't consent to? Vodacom needs to pull out the recordings of the call the day my upgrade was sent through and fix this problem, I'm tired of calling in and not being assisted! How on earth can it be legal for someone to upgrade a contract without my consent??? If this matter is not resolved ASAP, I will definitely seek legal advice!