Vodacom are ******* and put extra things on contracts without permission

I had two contracts with Vodacom that cost R512 including VAT for both. I cancelled the voice contract (R269 incl VAT) and on my next invoice, an amount of R43 was added on top of the R244 that I was supposed to pay and I immediately complained about it because Vodacom added the 50Min revolving contract that I did not ask for because they were simply trying to retain my voice contract. I was called by two consultants and was told that the R43 thing was cancelled and have been credited for it but come month end, I am charged R343 instead of R244.