Vodacom Cancellation: Shockingly poor service

I have been trying since 18 December 2020 to cancel my Vodacom contract without any success. Vodacom only accepts cancellations via their helpline, but the helpline employees disconnect the call when they hear that you want to cancel and not upgrade. Vodacom does not accept emails and their stores won't help - they say you have to use the helpline. The contract expired at the beginning of January and now they ********* me to pay cash monthly, otherwise my contract is in arrears and they say that they can't cancel the contract when it is in arrears. I have made 13 calls to Vodacom (not counting the disconnects) in this regard without any success. I have only received numerous promises, not one of which was kept.