This platform is famous and has an office/contact number, so I do not expect to be a scam exchange.
I've done research and there are no reports about hacking or people they have like your case.
Read some similar cases that have been resolved without having to communicate with the support team.[1]
Where you did not show the error message, suggest the following:
- Make sure you visit the correct site.[1]
- Check your Internet connection, stop any VPN, enable javascript, and reset your browser.
- Contact support team or call them Contact: +82-1661-5551
- Use social media sites[2] and Reddit.
- move this topic into Service Discussion[3].
[1]
https://www.bithumb.com/[2]
https://twitter.com/bithumbofficial?lang=en[3]
https://bitcointalk.org/index.php?board=85.0