Arm interview questions

Initially, I got a call from HR stating my profile is short-listed for PD and it is an urgent requirement. They scheduled 3 rounds of technical interviews in a span of 2 days. The interview was easy and went well from my perspective. I would give 9/10 for my interview performance. All questions were standard and the interviewer had the patience to listen to my answer. After the 3rd round no update. I called multiple times for results, initially, they told yet to receive feedback then they told me it was on hold. After some time the HR guy stopped picking up my calls and started rejecting them. No reply to my messages. I waited for 3 weeks and finally when I called another HR guy for the last time they told me it is a "No" from their side. Simply wasted my time and I waited 3 weeks for this result. They could have told it earlier itself. The reason for rejection also they didn't tell anything specific, just a waste of time and disappointment.