StorHub interview questions

Went to the interview via a 3rd party recruiter. Met the top guy in Operations and also did a case study for them. During case study, interviewer did not ask any further questions on my work. I didn't get the job and feedback was that they wanted a different candidate with a different skill set. The feedback for myself was generally positive. 2 months later, I now see the job being readvertised, it makes me wonder whether the job is actually available or the case study was used to extract free work/ideas.