Ask HN: How to deal with a domain impersonating my company, stealing accounts

Let's say I've got a company with the name and domain great-software.com, and someone started running a scam domain called greatsoftware.tech. This website tries to trick users into providing their account details and stealing their funds. The scam domain is registered with a Russian domain registrar.

Have should I go about this, and what options do I have?

Thanks a lot.