Uber Operation Manager interview questions

Good quality, but many steps. Talent aquisitor, then hiring manager and then two more additional steps with the assessment involved. The question asked in each step were having a level of difficulty medium

I applied on line and received and e-mail a week later to schedule an interview. Scheduled my interview via calendly for the fist available time which was a week later and spent several hours researching the days before my interview. The night before a received a calendar update rescheduling my interview for a 8 days later without an explanation or note, frustrating but understand things come up. I confirmed the day before my new interview date that it was still on, and the HR rep confirmed it was. Did further research, then woke up in the morning and received and email from someone else to say my interview was cancelled because my contact was ooo, and was promised I would hear back the following week to reschedule. I did not hear back, so followed up again. Received an apology e-mail and a link to calendly to schedule another interview. I did so, then never received a conformation or calendar invite. Again followed up, but this time radio silence. Very disappointing as I was excited about the opportunity and wasted time doing interview prep when I could have been applying for other jobs.