Mobile Phone Unlocking

My wife won a new mobile in a competition. Its a snazzy 3G phone - reviews were moderate, its not the best on the market but it is one of the smallest 3G devices in Europe. It came with a SIM card for another service provider, I rang them about exchanging the SIM for my own provider out of my old mobile. (I had bought my wife a new mobile only last week, so she was willing to let me have this one). The company wanted £150 pounds to unlock the phone. What a rip off! Surely, this is anti-consumerism and profiteering? Isn't this wrong and why aren't organisations representing consumers shouting to get this situation changed? I should have the choice whose SIM I put in the phone - obviously the phone and account type of the company have to be compatible (they are in my case), so the only thing stopping me using my nice new phone is the stupid phone provider. Things like this DRIVE ME NUTS!