balena interview questions

After submitting an application, I was emailed a few days later asking me to develop a feature for a smart home lighting application. At first glance, the assignment was asking for a lot. Upon further reading, it was unrealistic. They asked that you develop a solution for the application, then document the solution, then write unit tests, oh and if you discover a bug in the platform, open an issue. (free labor red flags all over the place ). They also state it should take you 3-4hours. Highly unrealistic. Although I was skeptical, I still completed the assignment because honestly I thought it would be fun. About a week later I received a 'canned' email response that they weren't moving forward. I didn't meet the criteria, and I didn't come up with creative solutions. This was hard to believe because the application I created hit every point they asked for and worked. They also said I didn't come up with creative solutions, but I'm not sure how creative you can be with a problem like this.