Cell C over charging on cancelation fees

I called the customer care department in August to get my settlement balance and cancel my contracts. I was given the wrong settlement balance and ended up paying more than I should have. I called cellc a few times to get this resolved and was told that the accounts department will refund the difference or credit my current contracts once cancelation is processed. The contracts were only terminated in October however they allocated the free minutes and data for October. I called in to enquire and was told this will be rectified and I will be charged only for the used freebies. Yesterday I see I was debited nearly 4 times what was supposed to be charged. I called the customer call line and was advised that I was charged a cancelation penalty for one line and he other HALF of my bill was VAT(15%).

This cannot go on. It's time consuming to keep calling the customer care line and getting pushed pillar to post and then being charged additional cancelation fees over and above what I already paid in August.