In order to hard reset a Sagem my312x, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Sagem my312x device will be brought back to the default configuration of a brand new device.
1. First, turn on the phone.
2. Next, go to Menu > Settings > Networks > Phone > Reset.
3. Lastly, select Yes. Wait for your phone to reset and restart. Voila.