Amazon Brand Manager interview questions

I applied online. A couple of weeks after I was called by HR for a screening process just to ask for my income and basic skills. Then they programmed a first phone interview with an employee with similar experience as mine just to assess career and culture match. The interview is divided in 3 parts: interviewer introduction, a series of questions relating your experience with amazon's leadership principles, and a practical question. All went good with the first interview. Then we programmed a second phone interview with the General Manager (manager of the position's manager) Interview followed the same structure as the first one. All went good until the practical question where the interviewer didn't provided enough information for the question and just keep on pushing with "what else?" questions, without exploring beyond. The question was "how would you know a category you manage is performing well?" That was it, no more info for a more precise answer. I elaborated my answer from objectives setting to all ranges of KPIs to possible issues and alternatives. Nevertheless I was just asked back "ok what else?" over and over again. By the end of the interview I asked to the interviewer how she would have answered that very same question, and came up with internal KPIs that I am unfamiliar to. A day after I received the notice by HR that they will not move forward with my process and that they are not allowed to provide feedback. So, I don't know if I was discarted because of my experiencie, values match or the answer of the practical question....and it seems I will never know. My reco is to prepare for the interview relating a professional experience (fact and number based) to each of the 14 Amazon's Leadership Principles (available online) and be ready for an ambiguous abstract question.