Contact BOOKMAKER here
https://bitcointalk.org/index.php?action=profile;u=174244 is what I would say if they are not responding to your emails.
I would say that do KYC and ask them if they are fine with giving the account and amount back if you do the KYC. It's not necessary that you are accurate with digital footprints as they say everytime as one's ISP can issue dynamic IP address and that can lead to a harsh penalty for someone innocent.
I don't understand why BOOKMAKER does not have negative trust if there are unresolved scam accusations... And while the KYC would make sense with other casinos, it does not seem to be the case with Jetwin. Just a month ago, he wrote the following:
We never ask our clients for KYC.
JETWIN is completely anonymous.
Unfortunately, he's also been inactive for almost a month now, so maybe he does not work for Jetwin or something happened to the owner of the account... And there does not seem to be anyone else replacing BOOKMAKER and answering to people's questions even in their ANN thread... Maybe it's just a matter of time before they find a replacement, and maybe the casino is just going down...