Ask HN: How to sue an international (crypto) company?

Imagine you have $200K on an crypto exchange. Don't ask why. Next day your account is blocked without reason. You can't even login.

How would you sue them?

Support tells you they are working on it but neither a reason nor progress is reported.

PS: This happend to me on Bithumb Global. It is totally unclear where the headquarter is. AND yes I did nothing shady, was just trading there since the last year.