Hi, just yesterday I was using an app on my phone and I thought the app wasn't working. But it turns out that the button I was pressing is right at the bottom of the sceen. I have now found out that the bottom about 1/2" of the screen does not work. So I cannot hit the phone button or the fave button or the arrow to bring up all apps. If the keyboard is up, the space and anything at the bottom will not work. The rest of the touch screen works normally, only the very botton does not. I tried a keyboard calibration, but I can't get through it because it will not recognize the space bar at the bottom. How can I fix this and what is the cause?