Problem with phone menu get invisible

Hello I need help.
I have 2 problems found during caling.
1. I called a Bank hotline. Jusual You nedd to press same number tu be connectet with right department. But I can't do it. Directly I want to press KEYBORD on totch screen on my M8 it turn off (blind off). han I push M button, I get phone menu visible and in this moment I try again pres sthing on scren it bling off. So I can not choose my number.
2. same problem but with eno of connection. I CAN NOT end connection . After I toutch scren on 'END' screen turn off. Connection is still active,

Please let me know.
Firmware version 0.9.0.4
production date of telefon : 2009.03.04
regards#
fic423

Sounds like you're covering the part with your fingers/face where the 3 holes are at the top of the phone. There's a sensor which turns off the screen so you don't push anything on the screen with your ear/cheek while on a call.

many thanks !!!!
I have a case with same connetion tin this area. Thia was a raseon.
Thanks again !!!!