Getting out of o2 contract

Fay

I have been with o2 for about 9 years now, they were Genie when I joined them and their customer service has gone from bad to worse. So now I want to leave them and move to orange as they have an unlimited text message deal on at the moment.

I just called o2 and the girl said that I renewed my contract in april for 12 months (true, they sent me a cheap nasty phone I have never even used) and that I cannot get out of my contract by any other way than paying up my line rental until april. Does anyone know if there is a way I can get out of this...she said she could change my tarrif but because I am an existing customer they can only offer me 500 texts a month, which I am already one.

I'm so fed up of their attitude, please help me get out of this contract asap!