I know that hitbtc has had a lot of issues because of withdrawal issues and so on, in that matter op I don't think I can help you in that matter. But have you tried sending a message
to their support about that? Because when the concern issue is like that, the chances of getting your funds back from the platform that you didn't release are usually low.

      Maybe try to make a scam accusation in this section op https://bitcointalk.org/index.php?board=83.0 this is if you have evidence that is held outside of hitbtc, good luck to you
and sorry for your loss.