Initial phone screen with HR recruiter immediately led to a full-day on-site interview. The on-site interview was scheduled within the following 2 weeks. The interview process took about 4 and a half hours, 6 separate interviews. I followed up immediately with thank you notes and within the day the Hiring Manager reached out to set up a follow-up phone interview. I prepped for it and cleared my schedule in the middle of work related travel. 5 minutes after the interview was supposed to start I had not received a phone call, so I checked the invite which stated that I was to call the interviewer. I immediately called and was put through to voicemail. I left a voicemail and immediately followed up with an email. I tried calling again 10 minutes later and immediately received a short, curt email that he would need to reschedule the call. I responded with my availability and never heard back. I followed up with the recruiter and also never heard back. The concern here is complete lack of respect for people's time. If they were not interested or thought that I was not the right fit, they should've communicated that as common courtesy given that I had already taken out so much time to go for an on-site and accommodate time for the follow-up. I found the process rude and it overall left a bad taste/impression.