btc-casino.io is a scam site.
I made a deposite off over 3 BTC in April and then wanted them to withdraw my Bitcoins.
Then they said that i have to pay a 20% withdrawal fee. And i agreed with this high fees.
But now after nearly 6 months i din't get my Bitcoins back.
So stay away from this scammers.
Go to open scam accusation thread against site on repectful part of forum. Bitcoin discussion board is not place for this kind of accusations. I hope you can find their thread through forum and complain to their support forum member.
