Olsen & Partners interview questions

Lengthy interview process that started fairly professionally then went massively downhill. First two rounds of interview went well. With their in house HR person always keeping me updated on feedback and progress. After the first 2 rounds, I was told you will be receiving a job offer on email within the day. Then they disappeared for a few days and started ignoring my calls. I needed to know if we are moving forward as they gave me a sense of urgency on starting the role and I had to set my affairs in order, in case I will start soon. They finally come back to me and tell me we need you to do 1 final meeting (not an interview) (and your job offer is being prepared). I went to that specific meeting and afterwards was completely ignored and discarded. Finally after following up with upper managers, I get a vague reply from HR that I was not accepted for the role. Honestly if they ever ask me to work for them again, based on this experience I would never want to. This gives me a sense of lack of professionalism, and work ethic from their HR team. I would even warn 3rd party recruitment agencies to be careful serving this business as judging from how their behave, they'll likely try to scoop candidates from you, without having to pay any commission.