Petition against Mobile Phone Companies Data Roaming Charges

Whilst in the USA, I used the internet on my I phone for about half an hour. I got charged £720. I'm with T Mobile and was getting a T Mobile signal in the States so I thought I would be ok. Apparently, I shouldn't have used the internet and should have switched the Data Roaming facility off. I really didn't expect to be charged that much. I think there should have been a warning. I have complained to T Mobile and they have said they will do nothing about reducing the charge. They did say, "We can understand that this is a very large amount to pay for such a small amount of useage." Well why charge so much then? The thing is, T Mobile data is cheaper in the USA, just like fuel, so I can't understand how the Mobile phone companies can get away with it. It is a scam! It is not reasonable, and many people are falling for it. It is spoiling peoples trips abroad. They are acting in a way that is morally wrong and surely must be illegal. Please sign this petition!