Initial phone screen with a recruiter before two rounds of phone interviews with the same manager, one thirty minutes and one an hour long. The interviews themselves were fine, however, the unresponsiveness and unprofessionalism were outrageous. My interviewer promised to get back to me with a decision on a certain date after the final round interview before delaying it, again and again, using all kinds of excuses, eventually even completely stopped responding without even giving a clear rejection. Wasted multiple weeks of my time, completely unacceptable