Lost Apple watch

Recently I lost my Apple Watch in a park. I think its Sport strap band would have accidentally opened while taking out my back pack and it would have dropped. I had setup Find my watch option which is added in Find My iPhone app, however this app is insufficient in case phone is lost. Every time I login to my account, it just shows offline. I have configured a message option that if someone gets my watch they will receive my personalised message with my phone number.

I wanted to check if Apple can really block this watch from use if its in Lost mode. Further, how can I be sure that if someone tries to use my Apple watch then I will receive notification.

Sound and lost mode is pending since few weeks now, is there a way to completely block usage of this phone.

Thanks

Amit