Hi,
Try a hard reset.
''Be aware that a hard reset will erase all your user data and downloaded apps.'' It will restore the phone to a factory default condition. It will be like when you first bought it.
Ensure that the battery is fully charged before you perform a hard reset. Do not leave the charger plugged in when you perform a hard reset.
Be patient, the reset takes a little time to complete.
Here is the procedure.
Turn off the device then:
Press and hold Volume Down key + Power Key for a while ( about 10 seconds )
Release all the keys when you see Lava logo
Press and hold Volume Down key until you see Factory reset menu
Press and release Power key to enter Recovery Mode
''Use Volume key to select Menu''
''Use Power key to Confirm or Execute Menu''
In Recovery Mode select wipe data / factory reset
press Power key to confirm
select Yes — delete all user data, press power key to confirm
select Reboot system now to finish hard reset.