Are you sure OP that you are visiting the right site? Because many claims that some people are using known sites and running such promotions but in the end, they'll get nothing. Their intention is to ruin the reputation of that known gambling site. I'm doubted that was legit promotion because they will respond to you if that is true but since they are silent and have no response, absolutely would think similar to what I think. However, it needs proof otherwise, it was a false claim...
That is true, if that is legit, for sure, they will disburse whoever wins on such promotion.
But if not, like promotion is already over, site is shady and others, don't expect that they will play fair.
The OP should elaborate more of this situation, because it is a case-to-case basis.
We will know what course of action to take depending on some specifics of the case.
Otherwise, we are just giving some generic answers towards this situation.