Few years ago, it seemed to be the beginning of 2013, I did not remember clearly, I've ever been scammed for nearly 20 BTC, I funded a gambling site, my account got frozen without any reason few hours after I funded.
I could do nothing except crying.
That's the worst thing you've done crying without doing anything, you should have gone to the authorities so they can trace who are the owners of this gambling site, you did not even mention the name of the gambling site if it is still online or ceases operation, but 20 Bitcoin is such a huge amount if this happens to me I don't think I would get over it.