My iPhone 5 turn off then turn on like restart.

Hello, I need some help please, some guy fix my lock button but after the fixed it, my iphone turns off then, it turns On like restart every 5 minuts or when I using it.

I call back this guy he told me that is the screen, but that's really stupid I dont think is the screen. I think is the battery, maybe this guy changed my battery.

Please can someone help me? what can I do??

I found on my diagnostic and usage data Panic.ips Incident identifier: BFBB2519 CRC ERR!

what that means??