Vodacom haphazardly increases subscription mid-contract

I've been with Vodacom for almost 20 years and unhappy for the last few. Phoned to cancel my contract and move to pay-as-you-go. The lovely, friendly, helpful lady in cancellations convinced me to re-sign an airtime and data only, 24 months contract for a great price. I agreed telephonically.

So about 12 months into the contract the price increases. I phone, only to get through to Tobi, a useless robot who can do the bare minimum, no option to speak to a human. EVENTUALLY get through, they have no decent excuse for the increase, and happily transfers me to cancellations where I'm through to the loveliest sales lady ever, again. She has no explanation for the increase, and after patiently listening to me rambling on, calms me and reluctantly sends me the cancellation forms. But there's a cancellation penalty. So I can't even get out of this stupid contract without basically paying the full year's subscription (at the increased price). This is ridiculous!! I didn't agree to a random increase whenever Vodacom feels like it.

So, there's no way I will continue with Vodacom after this. And the mere fact that they don't even respond to the Hellopeter reviews says a great deal about their desire for satisfactory customer service.