Lost iPhone's location not updating in Lost Mode

I lost my phone this morning and immediately called my family to put it on lost mode. The thief was smart and turned the phone off, which also prevented it from activating lost mode.

After a couple of hours, he turned it on and it updated the location and activated lost mode. Before I could try to trace the current location, the phone was switched off again and it won't update the location of my phone anymore.

Apple claims that you are able to track your phone even when it is switched off so why can't I see the updated live location even 5 minutes after the loss of network? Am I doing something wrong or is Apple giving false claims to give a fake sense of security to its users? FIled a police report as well, but they are also unable to help if they cannot trace its location. I have tried everything possible to try to track it with no luck, so if there is any solution to this please help.

If not, Apple really needs to stop advertising these false claims and improve its security.

[Re-Titled by Moderator]