Cohn Marketing interview questions

Sent a cover letter and resume via email to HR and heard back a couple weeks later. I had a phone interview with HR and heard back immediately about next steps. Then interviewed with a few team members. This all happened within 10 days and I kept getting prompt responses. Then nothing for weeks. I was told I would get some sort of update in less than a week. I tried reaching out to the HR director by email and phone. Then waited about a week and a half and reached out to the team members. Nothing. A month later I hear I don't get the job, so I ask what I can do to improve my interview skills or what I should seek in experience. No response. Bizarre going from prompt responses to nothing. COHN seems like a great company but if a communications company can't communicate, that will build a bad reputation and eventually show.