I can understand that, it's fire, and fire can hold for years, not days or months, so it's all normal
The best you can do is to prepare and get every piece of proof, screenshots, whatever you have. If you had recovery email address, you are notified that email has been changed, and that is a decent proof also. Think if there is anything that helps you on IG, some chat logs, go deep into every single detail.
Collect everything at one place, find/pay someone who you can trust, or friend of your friend in real life who is expert with info digging/hacking.
Send emails to scammer, not for phishing, but for IP tracing. Determine his base IP, his provider, get in touch with his internet provider.
Provider will refuse any cooperation by default, so leave that as 2nd option, and try to get a man from that company to get you his physical address.
Option 1 for his internet provider should be hacking company database obviously with assistance of WH or BH hacker (you know in real life, else you're scammed)
That attack is done by digging internet company employee list, and the very best source would be Facebook and other social media such Linkedin. (search for who works there)
Search for images and any kind of news regarding the company, who tagged inside the company (as a visitor) it is a very good chance they have friend employer there.
From there, hacker could investigate and serve what victim would open/click and eventually setup a backdoor to enter company database.
If success = his physical address will be found via base IP tracer.
If failure, or no friend hacker (do not be desperate) do not hire nobody from dark web or something like that, you are scammed 99,99,999% so better don't risk
(they will also ask BTC only, lost money)
Digging of employers you can do yourself, tracing IP you could learn yourself too (use google) and offer $ anonymously to employers for the IP owner address.
Mix up some story that employers could bite, and most of them are mutual friends, they can access to sensitive info, it's not some ultra breaking of rules or something, nobody will even know.
And try to make non BTC transaction with employer, so if he try to scam you, you can show him big list of his company mates and say: you better finish that thing for me or refund before everyone find out what you accepted.
Once you have his physical address, get a lawyer and use proofs from above to fight him in court.
This is probably the best possible solution you might think of. Hard, but possible. Good luck!
Edit: before court and lawyer stuff, you can scare him pretty bad (anonymously) should not be that hard.
And when he connect the dots, things might change without lawyer.
