I think I have made a blunder by using internet on my unlocked iphone. I had a blackberry and i switched to iphone and i had unlimited internet on it. Today i discovered that i had used 35 pounds worth of internet on my iphone as it was not connecting through the blackberry server rather it was connecting through o2. Please tell me a way through this, i have talked to the carphone warehouse staff but they said its irreversible. Also tell me if I will be able to change my data plan?