Hard Reset SAMSUNG Galaxy Ace 4

method:

1. First power off your phone.
2. Then press and hold together 3 keys: Volume Up + Home button + Power button.
3. When you see logo Samsung, then release all holded keys.
4. Next select option "wipe data/factory reset" -> use Volume buttons to browse, and Power button to confirm option.
5. Now choose "yes" with Volume Down, and confirm with Power button.
6. After that press Power button, to confirm option: "reboot"