Amazon Operations Manager interview questions

I applied online and received confirmation of a phone interview requesting me to selects slots that I was available for. The day after I received confirmation of a phone interview for a random slot disregarding my preference. The phone interview itself was easy, sounder very informal covering the usual questions about why Amazon, how have I managed KPIs before and how would I address poor performer. We then had a bit of a chat about the role and I was told that I would hear back within 2-3 days. The day after I had a missed call from international number but no voice mail was left so I thought it was spam. Week after the interview I contacted Amazon saying that I haven't received any update and if they could get in touch. After that I got email stating I passed first stage and I was given another date/time for second interview which I confirmed was suitable. On the day of the second interview nobody called so I emailed Amazon again and I was told that the interviewer was on leave and that they will reschedule when he is back. The day after I received email stating that they proceeded with different candidate, which I wasn't surprised about as another person who interviewed for the same job told me that he was informed during his interview that the job has been filled. Another friend of mine who applied for different job at the same time as I did had exactly the same experience. Very disappointing recruitment process and communication