phone freezing and unresponsive even after removing battery

phone seems to stop responding and pens the camera app doing nothing every time i switch on the phone.

It all started when I was showing my mom how to use the shortcut camera button after which it stopped responding and kept the camera app open.

i tried using the red button to switch off the phone but no use. I finally tried to pull out the battery 3-4 times of the moto v3i but same problem.

please help.