Worst service provider ever

Vodacom is the worst service provider I've ever had. I regret ever taking this contract with them. When I was taking this contract it was two hundred and something now I'm paying almost four hundred rand. Every month the amount increases. The last time I called them to asked I was told it's because of the subscription, I asked them to delete them & block them they told me they did. Again the amount increased, again I called I was told it's airtime advance which I know nothing of, I told them to lock the airtime advance option so but still the amount it still increasing. By the end of this contract I will be paying thousand rand. Each month it's increasing there's no fixed amount. Worst service provider ever.