Tried cancelling contract and being billed extra

I have a data contract with vodacom, taken out in Nov 2018. I called vodacom in September 2020 to cancel my contract when the term was up, which i thought would be the end of October 2020,i was told to only call in October as the contract was expiring at the end of November, i did so in advance as to give 30 days notice, i was told to call only in November, and the last payment would be in December 2020. My billing amount for the past 2 years was R280.87 (excl tax), my current bill for Nov 2020 is R342.96 (excl tax). This means that my contract should have ended in October 2020,but i was misinformed by vodacom, who instead of cancelling my contract, kept asking me to upgrade or migrate or take on another contract offering less data and was also told not to worry, as if i keep the contract the billing price would remain the same... And According to Vodacoms Terms and conditions this states it aswell on there site... "11. After the initial 24 months contract period, the contract will continue on a month-to-month basis at the price the contract was signed up for. This price will be applicable until the contract is terminated or the customer upgrades to another contract.".... So in the process of me trying to cancel my contract, knowing vodacoms terms and conditions, i get sidelined by there call center and on top of it am now being billed extra for the coming month.