As OP has more or less included, they were told the same via our on-site support. This was not at the expense of the player as they finished in profit on Rollbit.
But you've managed to equalize this by locking his account and claiming all the money he had there, am I right?
Personally, I'm fed up of the way casinos act in these cases. First you lock his account and when he asks why, you answer "we have nothing to say to you" but when he starts a thread here, to complain, you suddenly find the time to explain the situation. Why does this have to be the case each time? Why Can't you simply explain to the player why he's being banned from the site, so that he doesn't have to spend hours asking about it and explaining his actions to the whole community?