~snip~
But if the rule is from the site, and the OP make a mistake by himself, we can not do anything to help him.
^ This could be the first thing that we know by reading the FAQ or the TOS in a particular gambling platform because we don't know that we prohibit the rules without knowing us. So, in the first steps, we should read first everything on the first page of the gambling site to avoid possible trouble in the future like just what happened to OP now.
Nevertheless, we can't help the OP if we don't know the name of the gambling site. But instead, OP must contact the customer support of the gambling site if OP thinks the owner is a good guy.
And how many people read the FAQ or TOS? I don't do that, and in 5 years of crypto gambling I had only one issue with casino orrientexpress, I don't know how I got there but I deposited around $50, after few hours of playing slots I had luck to go over $200 and when I tried to withdraw they said you can't withdraw in btc, it has to be skrill or paypal or some visa, I can't remember now, it was a year ago, maybe more. I had a long argue with them, without any success of course, they keep repeating I should read FAQ, but for me it was crazy for site to allow btc deposits and to not have btc withdraws.
If FAQ says one, and OP tries to argue with that, he will just lose his energy. There's no help for him here. I had luck and I used my friends skrill to get my money, of course with some tricks, I had to make at least one deposit from that skrill and only after I was able to withdraw.