Last year I was really stoked for an interview with this risk analysis company and pretty sure I had a good chance (I have a master's in international studies,

Last year I was really stoked for an interview with this risk analysis company and pretty sure I had a good chance (I have a master's in international studies, which isn't much, but it's something). After they reviewed my resume and gave me an initial phone screening, which went okay, I was given an assignment to perform. I had 24 hours to write a risk analysis on this Crimean wine company and use my Russian language skills to research the company's ownership, history, and risks. I thought I did an amazing job, having written about 5 pages on them, citing numerous sources from the Russian financial times and other sites. Then, for the second interview, I talked to a member of their senior leadership (former US Treasury guy), and man, this guy was very much a jerk to me. He asked me, "What is the legislation that makes sanctions work?" I didn't know exactly, so I mentioned a recent UN Security Council resolution that added North Korean officials to US and UN sanctions lists. He interrupted me, saying that if I didn't know, I should just say so. I said I'm trying to tell you what I know. He said "Why didn't you prepare for this interview?" I said I read everything I could find on the company and did my best on the assignment, and did he see the assignment? He paused for a second, lowered his voice, and said "thanks, we'll be in touch" and that was the end of it. I'm still reeling from this, and this was over a year ago. I have every reason to believe that they used and profited from my research, because this company was recently in the news. I suppose this is a sort of crime that is nearly impossible to legislate against. Anyway, I am trying to improve my interview skills (and they did not reply to my request for feedback). Do you think I should have just said "I don't know"? I was always told _never_ to say this, but just to stick to your guns. But I got shot down by a snotty executive here, and it still hurts.