You're a casino online.. you're probably slamming the net with garbage content from garbage pbns/guest posts?
A lot of casino sites will rocket and then get smacked back to the ground. I'm sorry but content quality from non spamming sites are what you need and with casino... uhhh, good look. That's why I stay away from that niche myself. It can be done but why?
Then on top of that you are always fighting to be at the top and fight the hackers. Been there and done that with other similar niches.
If you can get it to work for you I applaud you and your patience!
Just remember you need to get your content quality, quality networks, then on those pbns/guest posts or whatever you should brand those pages so that they are given some "buffer" room just in case they are still viewed as bad quality links.
On top of that you should be using branding on all your major pages. Or if you can't do that create a page that then links out to inner links that are similar and then brand that page so that it all flows into those posts and they get a push upwards with a bit more trust.
Example:
Slots page with all your top keyword posts listed
build out a huge interlinking profile network
Sports betting with all your top keyword posts listed
build out a huge interlinking profile network
etc etc..
I would constantly be on the ground creating profiles with good high quality content, maybe dancing around the fact you're a casino. Find other ways to get your links up on these profile sites so the owners and users see it as either something of use, or at least a "shrug" and they move on instead of hitting the report button.
Casinos have a hard time keeping profiles. Make them real, and actually go back to them once in awhile, you'll find that has helped most of the people I've consulted in the past about these tough niches.
Just because I don't want to do it, doesn't mean I'm clueless on crazy niches.
Best of luck o_O