Early cancellation - vodafone/phones 4 you.?

I have had terrible service with phones 4 you and vodafone. i have just had enough and want to cancel my account after only 3 months. is this possible? someone else done this? when i was with carphone warehouse my insurance let me do this for a £30 fee.
Answer
I am afraid its not possible, you have signed a contract that binds you to it. the insurance would not pay to cancel your contract. the only possible way is to cancel is wait till you get half way through your contract 6 months for a 12 month, 9 months for a 18months. then you can downgrade to the lowest tariff and maybe pay the remainder which is the line rental x the number of months you have left.