Sorry in advance if this is a typical question but I'm slightly panicking that I've got a very expensive brick in my hands. I've just purchased a HTC Desire that was an unwanted upgrade by somebody on T-Mobile. As I'm an O2 customer I did a bit of research and found a website offering unlocking codes that seemed to have a good reputation. I gave them the IMEI number, the network it was locked to and paid. Minutes later I received the unlock code/pin and followed the instructions to the letter, I.E Insert O2 sim, wait for the phone to request unlock pin, and enter it. I did this and the phone went to the main screen. However in the top left hand corner there is a triangle with an exclamation mark in it and if I try and manually use the O2 network I get "Your sim card does not allow a connection to this network". Have I made a basic mistake or is the phone still locked?