DataCamp is a shady operation in my experience. I have no problem with the quality of the content, however I have personally experienced issues trying to work with them as a contractor and also have heard stories of similar issues from other candidate content authors. In short, they have no qualms about asking for content from authors in advance as a recruiting tactic and then telling the authors to take a hike. Of course, they keep the content as their intellectual property as use it as they wish.