hang-ups and mutes

[not2geeky]

While on a phone call my cheek hits the screen. This will either hang up the call or mute the call or even hit other buttons. Is there a way to stop this from happening? Is there a setting where the screen will automatically lock itself during a call so this will not happen?

 

[JCo352]

you might have a defective prox. sensor because it should automatically black out the screen when its near your face