iphone 5 doesn't end call and Siri problems. Need help.

I can barely open my screen before it closes and when I hit end call--it doesn't. The screen kicks off and goes black--anyone else experiencing this?

Plus, Siri is acting up and doesn't get the question and the screen goes blank quickly.

I was switched out for a new phone after all the other issues relating to lack of signal and battery drainage. So, I now have a new phone with a complete new install and now this. I have rebooted to the apple screen--nothing seems to be working to solve this.