US Fleet Tracking interview questions

I initially spoke with a PM, Brent, over the phone for about 20 minutes and scheduled an on-premise interview within a few days. The interview was with Brent and a lead developer. The interview lasted about an hour and a half. It was not very technical and felt more like a culture fit interview. It went really well, I felt. Brent said he would call me back the very next day to schedule meeting the team. He did not. Over the next 3 weeks I emailed him twice, Voicemailed him twice and linkedIn PM's him once. At that point I felt like I was wasting my time. Seems like a great company with a solid business model, but I feel this silent treatment is disrespectful and unprofessional.