In order to hard reset a Sendo M550, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Sendo M550 device will be brought back to the default configuration of a brand new device.
1. First, power down the phone by pressing and holding the Power button.
2. Next, plug in the phone charger.
3. Now press & hold the Power and 5 buttons simultaneously. Release them when a green tick pops on-screen.
4. Confirm the process by pressing Left Soft Key. Done! Wait for your phone to reset and restart.