When the game itself senses a traitorous kill, bomb, or balloon pop, the warning says 5 minutes, and you get 5 minutes. If a moderator thinks you are conducting game-ruining deeds and hits their Ban Button, you will see a 5 minute ban warning, but it will be for 24 hours (or more if they intend more and renew your ban after a day). If you cannot get in the game after 5 minutes, then a moderator did your ban. Or maybe a glitch, but I haven't heard of that one. Of course, new glitches happen all the time.
Either way, like everyone's said, go to Recent tab, look for Blacklist thread, and post your issue, your ingame name, and see if a mod replies after a day or two. They are volunteers so it can take a while.
Manfred