Uber Software Engineer interview questions

Talked to HR, then sent times for a 45 min phone interview with an engineer. They then scheduled the interview for a time I could not make. I replied and said I could not make that time, which they then said they would fix promptly. After a week of radio silence, on the day of the interview, I had an engineer call and email me asking why I didn't show up to the interview. After emailing HR again, still more silence. ???