I have AT&T, and got an international calling plan. When I first got here my phone worked fine, no problems at all, I believe it connected to vodafone hungary. 2 days later it's still connected to vodafone hungary but it says its on SOS mode only. This happened all of a sudden for no apparent reason. When I tried to buy an international sim, the vodafone people couldn't connect to their network either. I'm about to give up and buy a new phone with a pay as you go plan but i'm wondering why my phone stopped working in the first place.
