@OP to give you an idea on how effective advertising through the forum with campaigns is that the effect might only be visible to your company if you'll run in the long term. Such campaigns that do stay for a couple of weeks or months won't get the best results.
We are also interested in why Bitcoin mixers are advertised here and not on the dark web.
Most people there are already aware of how to keep their privacy thus, you may unlikely see advertisements there from a mixer. And mixer companies are likely aware of that so, the target market could be those that are still unaware of its existence and the brand that they endorse. My opinion could also be wrong about that.