Hi all, I recently bought an unlocked international version of samsung galaxy S GT-i9000. I was able to use it with at&t sim card quite happily till now. Even the 3g worked on it. But from yesterday the at&t service keeps disconnecting after using for few hours. The network bars at the top right disappear and a blue disconnected sign appears. I cannot make a call or receive a call till I reboot my phone. In settings->about phone I see that the "Service" shows "Not in Service". When I reboot it gets back to "In Service". Did anyone face this problem before? Is there any solution for it? My unlocked phone boots with T-mobile preset settings - is this problem because of that?\ Someone please help.