Hopper Data Scientist interview questions

I applied online, recruiter reached out and set up a chat. After that, I was given a 'Data Challenge'. It was pretty much trying to do what the company does( recommend whether a person should buy a given fare). I finished and submitted it and the recruiter replied within the hour saying the the work was great and that she received very positive feedback. Then I was set up with a call with another data scientist from the team to discuss the HW further. The interviewer himself was very young and had been working for only a year or so and was also saying some incorrect things about the problem. The call overall went really well and the interviewer said that he was very happy with my answers. Its been over 3 weeks since then and I haven't heard from anyone on the team. I tried to email the recruiter but its radio silence. It feels lie they basically took my HW, got their ideas and now nobody cares. Free consulting. This is not appreciated, I would at least expect a reason for not going forward given I spent over 4 hrs solving the Data Challenge. I don't understand how these companies that advertise as being fun places to work and the best place to work ever can do this with perspective hires.