There’s a similar claim on reddit (see https://www.reddit.com/r/DeribitExchange/comments/mmu9uk/deribit_account_blocked_and_cant_withdraw/), which may be yours, and that includes some details on the case.

The core option seems to persist with support, and interact with their own social media channels to give visibility to your claim. Pursuing them with a lawsuit seems a hefty task, since they are registered in Panama. You can also try to reach out to their CEO (John Jansen). I’ve seem he’s got a LinkedIn profile, but haven’t managed to see other more direct channels of communication. If you look around you may find better channels to reach out to him.