HR set up a technical phone interview for a specific date. The interviewer didn't call nor did they send an email to say they weren't going to be able to make the interview. I emailed HR and let them know that the interviewer missed the interview. They rescheduled and the interviewer called the second time. This initial phone interview was simple; they just asked about my previous work experience and some very simple questions about OOP. I got an email shortly after to confirm an onsite interview. They booked the flight and sent me all the details. Three days before the onsite, they left me a voicemail saying that the interview was cancelled without providing a reason.