Security Innovation Software Engineer interview questions

They gave me a task to make a custom URL shortener. The task which they gave was very open-ended so I made it how I felt should be good. There was a little bit of a naming issue with my code but overall I covered everything that was expected out of me. But all they had to say is that I won't be considered for the next round. Spending my weekend submitting a working solution that gets rejected because naming was not up to the mark. They expect specific solutions to open-ended tasks that they give. They might change it as I conveyed the same to them. But this is the only company to date which rejected because my solution was working.