Pearson Senior Java Developer interview questions

I applied through a Job Portal. The HR immediately responded with additional questions pertaining to this opportunity. After the initial call an online 1:1 technical screening was conducted with someone from the team for about an hour. After this I got call back for an onsite interview for 3 hours . During this time, I talked to various members of the Team including the PM and the Director of their Engineering Department. All was fine, I expected to receive some kind of feed back post this. Few days later I was updated from HR that feedback from Team was excellent and I would be updated with next steps. Couple of days after this, Since I did not receive any further updates, I contacted someone from the Hiring Team. He replied with an update an offer is making rounds with upper management, and you should get an update within few days. Few days went by again, I emailed HR with further updates she might have, To my surprise I was told I did not get the position and its already filled by someone else. The whole incident got me very confused, If they had no intention of making an offer to me why did they give me such updates. Moreover, as a reputed organization as theirs, least they could do was give me a correct feedback as to status of the interview.