Uber Research Scientist interview questions

The conversation with HR and hiring manager went very well. The next round was asking me to work on a case and sent back my code and PowerPoint to them within 48 hours. They sent me rejection letter a week later. I'm really frustrated with their feedback. They want to hire someone with some kind of skills. The case I worked on had nothing to do with those skills. Every candidate spends lots of time and makes every effort to prepare for job interviews. PLEASE respect other's time and effort.