How to reset CITYCALL I8550 when locked?

If you cannot unlock your CITYCALL I8550 and are unable to access the phone's settings, you may still be able to reset it using one of the following methods:

Use Android Device Manager or Find My Device. If you have set up Android Device Manager or Find My Device on your CITYCALL I8550, you may be able to remotely reset it using the web browser on a computer or another device.
Factory reset the CITYCALL I8550 using recovery mode. If you are unable to access the phone's settings, you can try factory resetting the CITYCALL I8550 using recovery mode. To do this, you will need to enter the recovery mode and select the "wipe data/factory reset" option.

To enter recovery mode on an CITYCALL I8550, you will need to:

Turn off the phone.
Press and hold the volume down and power buttons at the same time.
Release the power button when the phone vibrates, but continue holding the volume down button.
Use the volume buttons to navigate to the "wipe data/factory reset" option, and then press the power button to select it.
Use the volume buttons to navigate to "Yes - erase all data," and then press the power button to select it.

Note: Factory resetting the CITYCALL I8550 will erase all data on the phone, including any apps, photos, and other personal information.

If none of these options work, it may be because the CITYCALL I8550 has been locked by the manufacturer or carrier. In this case, you may need to contact the manufacturer or carrier for further assistance.