The Knot Worldwide FP&A Manager interview questions

I applied online and was contacted by in house recruiter. After the chat with the recruiter I had an interview with the hiring manager. The next step was case study. It was quite complicated and instructions were open to one's own interpretation. Two days after submitting the case study I got a message from recruiter that the feedback was positive and I was invited for another interview where I would be presenting the case to the hiring manager and another person. After my second interview the recruiter contacted me to say I was not selected and gave me some feedback from the hiring manager. I was told I was not selected for the final interview because of the issues with the way how I completed the case. I failed the case, fair enough then I don't understand why I wasn't rejected after I submitted the case. My time preparing for the presentation was completely wasted as I could have focused on other opportunities. The process took around 3 weeks from submitting application. The recruiter was quite good communicating next steps and arranging interviews but the whole experience was quite negative.