A friend has a Vodafone provided Nexus S. He recently switched to Telecom and now says he has no service in Tawa. I can imagine he has no 3G service if in Tawa if Telecom only has 850 and the phone only does 900/1700/2100 but he should have voice service.
I should check but I wonder if he has no 3G icon on the phone and think it means there is no service at all?