Go to the police and file a report, try to contact their domain registrar and hosting company, give negative reviews and post a scam accusation on bitcointalk.

This being said, it's extremely rare to see a scam victim being refunded (in fiat scams, and defenately in online scams involving crypto).
Most of the advice I gave is to make sure the person who scammed you cannot make more victims, consider it your good deed for today.