Cell C, Questionable Ethics.

I would like to know how cell c can change a month to month contract to a two year contract, and then simply send out an sms stating that the terms and conditions has changed. When I relocate to another country and try and cancel my contracts (which i thought were still unchanged as monthly contracts) I get told I have to pay a cancellation fee of approximately R1500. How in any way is this legal. And then they hide behind their call centre. I wonder what a laywer would say about the legality of this. They did not get any confirmation from me that it was OK to do this. As far as I am concerned , this constitutes theft, and wonder how many other customers are in the dark regarding this issue. Their only response - "we sent an sms" Strange when it's upgrade time, they call you, but when unilaterally changing a month to month contract to a two year contract, they don't, they just send a sms. With no guarantee that the sms will be read. Why am I not surprised.