for that campaign your deposit is very high regarding to the prize you give to participants so very low number of people will participate in your campaign. I think you have to start a signature campaign for your site and with the passing of time your site will make a place in this community and they themselves will start to play on your site for their entertainment.
Indeed the deposit is a bit high, but the reward is good enough for higher rank members. The 0.02 deposit is not a significant problem imho, because you do not need to spend it all on the games. As per rules, you only need to play 10spins/games means that you only need to risk around a half the guaranteed reward (0.008btc) for Sr. Member.
It is a +EV promo, isn't it?
Edit : They have started their signature campaign some time ago but they pause it. Maybe they think that the signature campaign is not too effective to promote their site so they decided to pause it.