1.
DON'T MISS GOLDEN TIME
Try calling it first and hopefully you'll hear it ringing or vibrating. The next best case is that someone picks it up and engages in conversation. For example, if you left it at a café and a good Samaritan retrieved it, you can arrange to get it back from them.
2.
LOCATE
If your smartphones internet was turned on then you can locate your lost smartphone easily simply try to borrow anyones smartphone/laptop and do these:
Try to locate your phone using Apple Find My iPhone, Google Find My Device, or Samsung Find My Mobile using App/WebsitendTECHroid
iOS: icloud.com/find Android: google.com/android/find Samsung : findmymobile.samsung.com
3.
FILE A POLICE REPORT
If you believe your phone has been stolen, file a police report. Although law enforcement agencies don't have the resources to investigate every case of a stolen phone, if you're able to tell them where your phone is (using a finder app), they will be more likely to be able to help you recover it. Bear in mind, it probably won't be considered a high priority case, so could take some time.
Even if you don't end up getting your phone back, filing a police report can help in other ways. For example, in some countries, devices that have been reported missing or stolen are added to a nationwide blacklist. This means they won't work with any networks in the country.
4.
LOCK (AND MAYBE ERASE) YOUR PHONE REMOTELY
As soon as you find out your phone is with someone else, the priority should be making sure that the person cannot access the contents of the phone. To do this, you can lock your phone remotely. The exact process will depend on your operating system:
@andTECHroid
iOS: icloud.com/find
Android:google.com/android/find Samsung : findmymobile.samsung.com
5.
CALL YOUR SIM PROVIDER
Call your provider right away to suspend your service. Additionally, if you're unable to perform a remote lock or erase yourself, don't lose hope just yet, as your wireless provider might be able to help. Give them a call, and they may be able to deactivate the device and possibly wipe your personal information from it. (It may depend on carrier to carrier)
Contact insurance company if you have opted any
theft insurance while buying your smartphone
no one's if I hope no ones phone get lost but if it happens now you know what to do...