I have an iphone 3gs unlocked by vodafone, have swapped to telecom xt, worked find a few weeks now it keeps say searching then no service and your celluar network has been lost, have tried reseting network, full restore, xt apn settings but nothing has work. I test it on another xt sim and same no service, but works fine with vodafone and 2degres, sometimes it finds network after 1 night having the phone off bt then goes back to no service. Please help thanks.