Dear @jainamit1980. We are sorry for the problem and inconvenience. May I know what is the last thing you do with your phone? Did you root your phone?
Lets try to do factory reset first.
Please kindly backup all your data first before doing The Factory Reset. There are 2 way to factory reset your phone.
Warning: this action will erase all your personal information, files and downloaded apps.
In power on state:
Click " Settings" -> " Backup & reset" -> " Factory data reset" -> " reset phone"
In Power off state:
1) Long press Power Key and Volume Up Key
2) Use volume up key to select "Recovery Mode" and use volume down key to confirm.
3) Press Power Key and Volume Up Key together twice to enter recovery mode.
4) Press volume down key to select Wipe data/ factory reset
5) Press volume down key to select " Yes---delete all user data".
If the problem still existed, please contact our service center on http://www.flash3c.com/support/service-center/