Terrible service by Vodacom SA

I had a Vodacom data contract with Vodacom for the past two years , the contract came to an end in November and at the beginning of November i called their call center to give notice of termination of the contract , the call center agent gave me a reference number for my request but to my surprise Vodacom kept on billing me for the contract which i called their call center 2 times afterwards. Each time i was promised that my money will be reversed and that the contract would be terminated but till today ( February 2021) Vodacom is still debiting my account. This is an unacceptable service by Vodacom and no one is willing to help