I bought an iphone in March and I'm having problems. Sometimes when I'm talking on the phone, when I bring it away from my ear the screen is black. I can't disconnect the call, if a drag my finger across the screen, the desktop flashes where it sends endcall but it goes black and I can't end the call. Sometimes the screen stays black for minutes at a time. I often have to shut the phone down and that takes a long time. If I make a call and need the keypad to put in an extension the screen is black and I can't complete the call. Anyone know whats going on?