The Stellaris mobile spinoff steals Halo assets.

https://forum.paradoxplaza.com/forum/index.php?threads/stellaris-mobile-halo-artwork.1259029/

Probably nothing can get done about this because it's outsourced to China and we know what they're like for respecting copyright and intellectual property, but I know I wouldn't like it if somebody stole something I'd worked on and made money from it.

Is there an official business email I can send this to?

I just saw that myself, and yeah - given where the game's coming from chances are not much will come of it. But, chances are also good the game won't live for very long anyway and in time people will forget that that Materialist Leader ended up sneaking off with a few Scorpions and Warthogs.

It won't change that it happened though, sadly enough.... Maybe in the future Paradox will be a little more careful in who to partner up with when developing side-games like this.

I wonder if Microsoft had anything to do with the game being pulled. I wouldn't be surprised if Paradox was contacted by Microsoft at some point about this. That said, I also find it just as likely that Paradox found out about it and pulled the game without any communication with Microsoft.
Either way, the game is thankfully shelved. Stolen art aside, the game seemed pretty unoriginal.