anyone help with phone contracts

[Matt]

basically i have an iphone 4s £35 a month, unlimited data calls and texts.

or so i believe



apparently my bill this month is 170 odd
when challenging them they have told me that i probably got the internet unlimited as a 3 month grace period, and thats expired.

thats all well and good but my contract is nearly a year old. ive said im paying the charges due to not being made aware that my contract has been changed, plus i was never told it was a grace period atall.

now ive got a f*cking huge bill to pay and not a penny coming in.

can i cancel the contract? as they are f*cking me about and i cant even afford the contract now im jobless anyway