Cancellation Nightmare

I initially had a contract with cell c. Which was expiring end of November 2020. I got a telephone call from Mrs tofu for an upgrade from 20GB to 30GB for R289, which I agreed to. The following month I found out that she migrated my data from 20gb to 500 mb. Expecting me to pay the same amount. I queried it. And I was told by different customer care consultant that it must be investigated which will take 3 working days. After a week I haven't gotten a call. I then called them back numerous times after being put on hold. Eventually I got hold of a different consultant to the first. Which told me that there's no investigation being done. Which infuriated me. He then logged my complaint and gave me a reference number(which I have lost since then). After another week they never got back too me. I had enough of their poor customer service nd cancelled my existing contract as well as cancelling the upgrade. January 2021 I got debited an amount of 207 by cell c. Which I reverse and then 26 February 2021 I got debited 805 which I was not made aware of. I tried calling however no success, I then went in to the store. To find to my amu*****t that they never cancelled my upgrade and went ahead with it after I told them I'm no longer interested in their service and they should've cancelled it in October 2020 already. This has been frustrating months of calling their call centre and visiting their store however still no conclusion and my account still being debit!