I have had my Samsung Nexus S 4G for over a year, the other morning I was unable to recieve or make any calls (no dial tone). I looked up the status under system settings and the mobile network state said it was disconnected. I have spoke with Sprint customer service, taken my phone to the sprint store (they worked on it for over an hour) they reset the factory settings. I have also chatted with Samsung customer service. UGH HELP???