why are u so inconsistent with your bitcointalk challenges. you did the bitcoin prediction challenge and stopped abruptly. you did the second one and again stopped abruptly. what is the reason for this? you always stop without any form of explanation
Nothing personal here but your post sounds a bit unfair to me : they run one one of the longest if not longest bitcoin price prediction contests, they reached the 72nd round of it; if you consider every round awarded at least $ 150 ( not considering the 20% bonus winning for the first 10 posters eventuallly right on their predictions) withdrawable straight away form their site we are talking about more than 10 grands given away to bitcointalk users.
Regarding the recent slot multiplier contest they "only" reached fifth round but like most of their competitors they stopped at a certain point because the participation is not that massive lately ( maybe it never was) and being them a business and not a charity they did some math and stopped it. Nothing wrong imo.
Aside from what you have said, there is also no obligation for Jacksclub to tell him the reason why the stop their promotions. They can do anything as they wish as long as they stopped it fairly. All in all, the casino can start and stop their marketing or promotion as they wish without telling people why they do it.