It is mysterious if Duelbits team haven't blocked your account completely despite knowing about your multiple accounts.
Maybe because I wasn't breaking any TOS? It could also possible that I was winning from the leaderboard and they don't want a winning customer. Who knows only DB can answer those questions because when I asked support they only provided me a generic response that excluding me was from the decision of their marketing dept.
As @avp2306 and @mahdirakib alters pointed out, clearly you violated the casino ToS on multiple account.
However, you are not abusing their bonus that’s why they let you off the hook rather just exclude you from marketing which is not new even for single account user only that frequently winning through their tournament and bonuses.
Most casino don’t reinforce immediately the multiple account policy if you don’t use it to abuse casino promotion.