Applied online, had phone interview, called into office, got offer

I got a call from the HR to schedule a face-to-face interview with the hiring manager directly. During the interview the manager did not seem to be interested as he did not ask any questions and just kept looking down at my resume. I was the one who went on asking questions. Its been 2 and a half weeks but I have not heard back from them. Its an extremely unprofessional behavior on their side to not inform the candidates about their decision after being called for an interview.