Ok, here's my situation: Im having trouble receiving calls with the iPhone. I have my phone in Sleep mode (the screen is turned off, but the phone is on) and when i call from another iPhone or another line, it doesn't do anything. The screen don't show there's a call coming in, etc. But in the other line (the one when i'm calling from) it's ringing. It even rings out and goes to voicemail. My iPhone still doesn't do anything. But when i wake the iphone, it says on the main screen that there is a missed call and even a voice mail waiting. Its strange because the signal bars are maxxed out in full. I called ATT to see if it was a signal problem, but they reset the signal and still no good. They tell me that the phone is defective because if it was a signal problem, the phone when i wake it up wouldn't show that there are missed calls, or any voice mails pending. Its weird because my friends iPhone is right next to mine, and his dont show those symptoms. What do you guys think? im taking it next week to the apple store, will they exchange it? Im i the only one with this problem>?