So, when I make a call on my Lumia 920, I can't stop it becasue the screen will just go black and shows nothing. When I hit the ON/OFF botton several times, the screen will just flash for 1/2 second, and then go dark again. That means I can do nothing when I make a call on my lumia 920. If I make a wrong phone call, I can do nothing to stop it. What's wrong with it??!!