This is ridiculous! How can you entrust such a huge amount of money to a third party exchange which can not be trusted,. They can not be trusted as there has been complaints from members about their activities and how they were treated. This exchange does not have any good record to compliment their existence, neither do they have conscience.
Did you not do your due diligence on the exchange before making use of their platform? I am wondering what gave you that confidence to make such a huge deposit with them or have you not heard about the hacks that happens to exchange?
I will advise you do not make such a silly mistake next time and do well to conduct your due diligence about any exchange platform you want to use and always remember the slogan "not your keys, not your coin"
 You should contact holydarkness if he can help you out because what I know about his activities here bis basically contacting casino's on behalf of members to resolving conflicts. Maybe he could help you out with your case.