Extension of contract without my consent. - Consumer Complaint for Vodacom - Head Office

I had cellphone contract( cell no: 064 652 7603) with Vodacom which was suppose to end in February 2021.Vodacom refuse to end the contract as they keep on loading airtime every month at increased price without my consent. I called so many times trying to get them to cancel the contract, but they're always telling me that the issue has been escalated or they hang up the phone.