FortuneJack is one of the long running casino that is announced in this forum. They even spend money for advertisement and has one of the longest running signature campaign in this forum. I think you need to be patient for the result of your KYC.
Have I been scammed?
I think you need to wait a little longer to know if you have been scammed or not. Don't just jump into conclusion or think that you have been scammed without waiting for the result of your KYC. I have been a FortuneJack player for years now and I do not encounter any problem in withdrawing funds after I passed the KYC (this is my own experience and might not reflect others).
Although they have higher minimum requirement for withdrawal, I think they are reputable enough to trust as long as your account do not encounters any problem that conflicts their TOS.
But for 600 bucks lol, I hope it's not the case.
Anyway, I do not think they will tarnish their reputation for a small amount of $600. Your withdrawal request will processed soon after you passed the KYC.
I believe this was done by another casino and not by Fortunejack. This might be misleading making reader thinks that fortunejack do this kind of stuff if they just read the qouted message and not click the source of it.