Kaiser Permanente interview questions

A one-on-one 15 minute screening, then a consulting case interview with multiple members of the team, and a presentation about a project you've worked on for work/school. I got past the case interview and successfully presented my project only to never hear from the team again. Considering I spent around 30+ hours prepping for these interviews, was involved in this interview process for upwards of 6 weeks, and sent multiple follow up emails to the team members I had been in communication with for this whole period, I found this to be extremely unprofessional. Failing to even send an automated rejection email after such an extensive interview process is quite telling.