Not getting paid seems alarming, but on the surface it doesn't seem like a thing we would be involved in. Level isn't owned by Medium and you are free to create whatever deal you want with them. We don't have any visibility into those deals or any ability to enforce non-compliance with a contract you've signed. I'm saying no both because it's not our place but also because most often because we literally have no power. You maintain the copyright to your work and only you can license it out or enforce a violation of your copyright. We literally have no standing legally.