My AT&T iPhone 4s OS 6.0 worked fine until today. The problem is that the voicemail indicator does not indicate when a voicemail is waiting. No badge number, no highlighted icon. I can call in to check my voicemails, and they are there, and the calls that came in show in the Recents list- just no indication that a voicemail is waiting for you. Any ideas? Google didn't turn up anything useful.