This is daylight robbery. No point in playing with these highly unregulated bitcoin casinos I suppose. Check if they fall under any regulatory, if they do, ask for an ADR. Else, proceed legally.
They are one of the "licensed" casinos. Please note that nearly every issue a gambler reports, almost bar none, stems from a site licensed in Curacao. Being licensed/regulated as a casino is next to meaningless since every country handles gaming legislation differently.
As for the OP:Unfortunately it sounds like you broke their T&C (which is crazy). Something most don't realize, is that at many casinos, bonuses actually lower your probability of walking away with profit. As a general rule of thumb, avoid any casino site that is deploying "licensed" software. You are not only chaining yourselves to their initial bonuses (most require very high turnover rate, while also minimizing the max bet size), but you are playing at relatively ridiculous house edges. You would have a much better experience (not to mention never being asked for documents if you happen to win big... funny they never ask for documents when people lose) if you played at a provably fair Bitcoin casino.
Suggested casinos to check out:
PrimeDice.com
BustaBit.com
MoneyPot.com (disclosure: I am a partial owner of MoneyPot)
BitDice.me
All of the mentioned sites above have been running for 1+ year, are provably fair, and have solid customer support. Oh, and the RTP will be considerably higher than what sites like Casino Extreme could ever offer you.