ubirch interview questions

A first call (visio) with the CTO during more than one hours to explain what they do, what they are expected from you and present yourself. A challenge has been sent to me, I had one week to do it (problem about competitive access management) A second interview(visio) with an experimented developer to talk more about my experience, and how the engineer's team work, I didn't have feedback about my challenge. And a final interview with the new head of engineer, to talk (again) about my experience, unfortunately, she just arrived, so she couldn't talk a lot about its vision of service, she didn't check my challenge too. Finally, a simply mail sent to say that they didn't select my application. And I never get a feedback about my challenge