Contract cancelation gone wrong and false discount offered

I've been a good customer to cell c, till where I had to cancel my contract in June 2021,the consultant who was helping me over the phone said to me I'll be paying my last installment in July, surprisingly so in August I was still paying it, I had to call and inquire about it and they said it will be solved they are opening a case for me I must wait, another thing happened again in August I was offered a 10gb day and 10 gb a night for R149. 99 monthly I agreed when my statement comes month end it tells me another story about my bill, when I called again it's said a discount was not loaded on my account and a case must be opened for that, when you call to find out the outcome of the case they will tell you the case is closed I have to reopen another one while they are debiting my money monthly, yoh! Cell c your a **** shame, I won't be paying anything into your account till you fix my queries, how many cases must one open? All my queries are never solved since June till now, my account is not up to date because of the disgusting service you giving me.