Lost Mobile

Try bahs. Does the location keep changing? If it does, then likely someone has gotten hold of the phone alr.

Have u tried to call back ur phone? I suppose that ur sim card is also in that phone, unless u have informed ur telco about ur lost phone and requested for a new sim card and that old sim card will have been terminated.

If cannot find whether lost or stolen then better factory reset it remotely to play safe. Or u could remote lock it too

Ah okay.. so if someone tries to sell it, the mobile shop seller will try to verify the IMEI and be prompted with an invalid IMEI, then the one who tries to sell away the phone will be suspicious.

From there i'm curious if they either get the police involved or just surrender it back to Samsung

This I am also not sure, if Samsung side will have knowledge of the lost phone. If they have, then will be easier to identify if the new user (may not be the culprit, as only bought phone from mobile shop) visits the service centre for repair.