Have you created a scam accusation to them as based from your posts, over $5k is not small money to lose? If you will create a formal thread on this board, they might resolve your issues or at least give partial amount of your money -

https://bitcointalk.org/index.php?board=83.0

And also, users will come to know this potential problem on this exchange. I won't use this as I've read negative feedback on them.