Vodacom contract change

I have two contracts with Vodacom, both of which are uChoose Flexi 230, with 2GB data/month. Although the contract is great for me and my wife, there is a huge problem with it lately. Vodacom has for some maraculous reason decided to change their T&C. So now my airtime doesn't accumulate anymore, they have now limited that and you forfeit unused airtime every month, so only max 2 months worth airtime can be accumulated, no more. Not long after they've changed that, they now changed the data accumulation too. Where data used to be valid for 60 days, you now forfeit contract data at the end of the month too. So all that unused airtime and data, Vodacom just takes it back and the customer looses out. I've now phoned to address this issue before and was told that Vodacom doesn't have to notify their customers about their change in T&Cs. So again the customer looses out while the industry suppliers get away with *****ing from the customer again. It's like a bank *****ing R10 from 100s of customers each month and getting away with it. Vodacom changes their T&Cs just to make the customer loose out. No one was loosing out before they changed anything, but that's not good enough, Vodacom wants to be on the winning side regardless.