Something strange happened when I registered on BC.GAME. I was using Tor (which is the browser I usually use) and when I saw that it wasn't working properly, I switched to a normal browser. When I finished registering, a message appeared saying that I was not eligible for a bonus because someone else had already registered from my IP address. I don't think that's accurate. What happened was that the system registered my email address when I was using Tor even though I didn't finish the registration, and when I registered with that email address in a normal browser, the message appeared.
When you use Tor, you likely use same exit nodes that are used by many other Tor users. It is the issue but I understand your concern like why you did not complete your account registration with Tor, as it was not allowed by BC.Game, and later you registered your account without Tor, it was still flagged.
You did not describe extra details like whether you clear your browser cookies entirely after a failure with Tor, before register your account without Tor. I guess you did not clear browser cookies before trying it again.
If you did like this, it is the cause, and I believe that if you clear cookies before trying account registration again, you will have no problem.