Welcome to TinyDeal.
The phone turn off automatically, here are the steps to help you
First, please make sure the battery is not empty,
Second, please check the battery’s connection is tight or loose,
If the battery is loose, you can place some paper beside the battery to make the battery’s connection is tight,
Could you also change another battery to check again?
Any questions please contact us by Customer Service Express: https://help.tinydeal.com/contact-us