In order to hard reset a Hisense S518, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Hisense S518 device will be brought back to the default configuration of a brand new device.
1. Turn on the phone.
2. Go Menu > Settings > Reset > Master Reset > Yes.
3. Tap in the 1234 safety code.