I have AT&T and i recently discovered that when I'm connected to LTE (have it enabled) my iPhone 5 will not receive calls. The iPhone says I have full service or at least 3 bars, but when people call it rings once and goes to voicemail. When I turn LTE off I am able to relieve calls. Is anyone else having this problem? Or know how to fix this? It's been going on for about a week.