The Scalers interview questions

I interviewed with Scalers for a HR role but that didn't go through. They asked me to make a ppt and came back after some days stating 'oh it was too simple and expectation was higher'. I was like okay because Well! how do I know how fancy of a ppt they need. But few days later they called me again that they have another position for a client and my profile matches it. I had 2 rounds of interview and it went really well. In the 2nd round I got feedback like 'You're a perfect match for us', 'We would love to have you in the team', 'Your experience is very relevant'. Hearing this kind of positive feedback I was excited for the next round to meet the onsite team. It didn't happen for a week. I followed up on the same but didn't receive any update. I requested to expedite my process since I was available to join immediately. They said the team is busy but they will try. And on the day I requested them. they suddenly informed me that sorry you are rejected, the onsite team selected another candidate. I was stunned that after getting such positive response, how can a candidate be rejected without an interview or a plausible explanation. Very disappointing and unprofessional experience. I would definitely skip interviewing with such an organisation in the future.