I lost my cat, and I know who might have him, but I only have their Facebook. What should I do?

[Pia]

I was scrolling down my news feed, when I came upon a picture of a cat that looks MORE than similar to the one I had a few months ago, but unfortunately ran away. I contacted the page, who then sent me the persons Facebook account. I contacted the person who shared the picture, yet they argue that they've had the cat since it was 6 weeks old. Now, keep in mind this cat has unique features, and I can tell my cat out of 1,000. My cat was my whole world my heart broke when he ran away, what should i do?
- And no I cannot meet up with this person.
-The cat has distinctive features, He has a batman mask on his face, I dont think nature can make that happen twice...
-And yes, the cat is micro chipped