My iPhone which is the second one I had, the same problem has occurred in both phones. The screen goes black when I’m talking to somebody and I can’t hang up the call or when I get the green thing that says touch to return to call as soon as I touches it, it goes black again. I went to Apple store at 10:00 a.m. and was told I could have an appointment at 8:30 p.,m. I told them if there were that many people wanting to see them, they definitely had issues with the phone. Another really irritating thing is when you’re on the phone to people, unless you “hide” the keyboard my ear hits the mute button and people can’t hear me. I HATE this phone……..