The Maverick Group interview questions

I had 2 interview stages, first stage was where the group account director told me that he likes to have a breadth of choice so he already interviewed 12 people for the role and plans on interviewing 5 more after me as first stage. I was then offered a second stage interview where I was given a set of 2 tasks to present on. I went very thorough and spent a few hours preparing the presentation. The interview was with 4 people, all asking questions and looking at me piercingly which was overwhelming. Then I haven't heard from the company for 10 days at which point they told me the decision hasn't been made. Over 2 weeks later upon me sending an email expressing my dissatisfaction with the way I was treated (i.e. no comms at all after the interview) they replied confirming I wasn't going to get the offer, which I gathered anyway. Very unimpressive way of treating candidates.