Vodacom increasing subscription without client's consent

Vodacom has committed an act of ***** on my cellphone contract. How is it legal to alter the terms and up the subscription of a contract without me signing for it? What's even worse is that when you dispute the altered invoice their arrogant agents will sell you the VAT increase story. When you prove to them that you understand VAT increase and that it doesn't amount to what they are charging you, that's when they become even more arrogant. I even went to a vodacom outlet and they speak the same language as call centre agent. I'm convinced that this ***** is well orchestrated and evey agent is well trained to lie to customers.

I never requested or signed for the additional 150MB which I'm made to pay over R40 more on my contract for it. I signed up to pay a fixed amount for a period of 24 months.

Please resolve this matter and reverse the ******** changes made to my contract.