Mobile phone contract

[phr33k]

I think this is the most appropriate place to put this.
My mate recently told me that he recieved a text message from Orange (other mobile phone providers are available) saying that changes were to be made to phone call charges. He rang Orange and cancelled the contract because it's not the contract that he signed up to, therefore potentially a breach of contract?
I've had basically the same text from T-Mobile, does that mean I could cancel my contract? Wanted your opinion before I went and tried to cancel it without a leg to stand on!