It's not the money, it's the fact they said they only reward players who lose. It's left a really bad taste in my mouth. They didn't even try to escalate to a manager or find an alternative.
I'm not much into sports betting but I've heard it's commonplace. I have even repeatedly heard stories that in Spain winning players are banned from sports betting after they win a certain amount, which has always made me doubt the legality of the action.
I think you will be unable to convince them if you don't do anything about it. It's their loss if they will not make you stay with bonuses. Do they have that promotion anyway? And does it happen to other users as well?
Their loss? I don't think so. Correct me if what I say is not correct. In sports betting you play against the house, therefore a long term net winner, no matter how much he bets, what he does is create losses for the house, hence the low interest and the fact that in countries like Spain they are forbidden to play.
It is not like in poker for example, where the house takes its commission even if some players are long-term winners, and even in this case they are more interested in the losers.