They sent an email to me to let me enter the time availability and I sent it back, but then I never heart form them anymore. Besides the email I replied about the time schedule, I sent an additional one asking the status but I don't get their replay, too.

I was notified by headhunter directly to have an on-site interview. I had three rounds with people from different groups including COO, Head of Engineer and HR people. The interviews with Head of Engineer and HR go smoothly, our conversation focuses on recommendation system and team culture. The conversation with COO is the most awful experience I ever had, she's pretty distracted that she didn't pay attention to our discussion and reply. The phone rings during our conversation, and she stared at her laptop without any eye contact. The funny thing is when we discussed how we can build recommendation system, it seems that she know nothing about recommendation system. One surprising question I was asked is "how you can bring your previous experience to our team", it surprised me because I have spent 20 mins on my previous projects and proposed methods to build recommendation system. I don't understand why interviewer asks questions that she has no idea and basic knowledge at all.