I doubt sportsbet vitcim was a multi account abuser, I mean sure he was definitely multi accounting but that doesn't seem like the reason he got banned. It looks like he was banned because he was trying to double spend, no matter how many times he could say "there was no confirmation, I didn't realize" or whatever in the end if you end up betting with the money that you haven't sent to sportsbet, in the end you are suspect of double spend easily.

This doesn't mean sportsbet is scam, it means you have tried to play with money that wasn't even in sportsbets vault yet which is a bannable offense. He probably did this with many accounts as well where the multi-accounting came to play, if you end up losing you are losing nothing since you haven't sent any money but if you win you are winning so it is a great strategy until you get banned.