download free tool https://www.4shared.com/rar/ImWfwPzviq/VIVO_Y71_User_Lock_Removal_Too.html?
turn off the phone hold vol up+power to enter recovery
reboot the phone with adb
insert usb and install driver if needed
go to device manager and look for the port of your device
open Y71 use unlock removal tool
type the port number of your device and hit the button below
the phone will reboot to factory reset
wait untill done
