Nubank Full Stack Developer interview questions

I was first contacted via LinkedIn by a NuBank Recruiter, after that, we scheduled a 1 hour HR Interview, everything seemed ok until that point, so then, they sent me Full Stack assessment, however, in reality, that was a pure Front End assessment. Basically they wanted a scalable, simple interest calculator based on a provided design, they encouraged to use JS or Closure (without any framework), functional programming, and it should take a JSON object with a structure provided in the instructions, and also, it should output a JSON object. I built the app from scratch using a scalable design pattern, with a well-tested, clean code, and responsive UI. However, after more than 2 weeks waiting for a response (and trying to reach them for a confirmation email), I got an email with a response notifying me that they wouldn't be moving forward with my process. I'm still waiting for the technical feedback, but based on other reviews that I read here I'm not sure if I'll get it, or at least an objective one. In conclusion, I feel is a waste of time to apply for a position in this company, If you get contacted by them, think it twice if you are going to start a process.