Computer Science for IGCSE & O level - The Internet And Its Uses (Section 12 - No. 2)
What should you do if you lose your mobile phone?
Do nothing, it's probably fine.
Immediately contact your mobile carrier and report it lost or stolen.
Wait a few days to see if it turns up.
Post about it on social media.
Forklaring
Reporting it lost or stolen helps prevent unauthorized use of your device and data.