I recently purchased outright an AT&T Compel Z830 Go Phone in the US. I am within good standing in my contract with AT&T and have already met my contract agreement. The phone is a quad band GSM and LTE 4G capable phone. I called AT&T support to give me the unlock code so that I can use it in Europe. They provided me the code and when I entered the code the phone seemed to unlock when I put in the non-AT&T sim. When I checked the Mobile Network settings I have the availble settings for teh GSM/WCDMA which was prefered by the T-Mobile carrier. i have selected that setting but the phone fails to find the network automatically and if I choose T-mobile carrier the phone still does not have signal to register on the network. Any suggestions?