Incorrect billing not attended and basically told to live with it.

I had a 24 month cellphone contract with Telkom commencing in 2020 April, which ended in 2022. And since 2022 I have been on a month to month benefits contract (data and minutes) as the initial contract had come to an end. Lo and behold, last month I get a call from Telkom to upgrade my benefits for another 24 months, I told them I had no problem with that but I will NOT be taking any device. That was all good and well until I received an invoice where I was charged R829 for "Device Obligation", called in on the 4th of March and no response, then on the 5th I received a case number ***4 and promised response within 72hrs. Two weeks later today, I call again and I am told the matter has not been attended to and will be escalated and there's nothing else they can do for me. And come month end they would want to debit me. I will reverse the transaction because I don't pay for things I do not have knowledge of, but that will be bad for my name at the ITC. Telkom stop being *******, what is that obligation for? I don't want this contract anymore.