Booking.com Data Engineer interview questions

The first part of the process consist on a hacker rank test with two algorithms question. After the submission of the hacker rank, the tech recruiter reach me to have a start conversation about the role and the company and how the following steps would happen. The conversation went pretty clear and the recruiter did an awesome job to explain everything and all the benefits and process. The next step was 3 interviews, one related to algorithm really close to the racker hank test, then the next one was a design system solution related to a big data environment and the last one was a hiring manager interview. the last part was the proposal with the recruiter after the three technical interviews.

4 rounds interview. First was hacker rank online coding, second was code pair round where you need to code in front of 2guys, third was system design round where you have to develop solution and final was cultural fit round. Before last round , HR was so sure about my selection that she shared me the rough idea of salary structure for my review if I am ok or not. When final round went good, their colleague came with status as reject without giving me the feedback of last round. Instead their colleague wrote, you rejected due to system design round whose feedback were already shared as positive and they gave me go-ahead for final round. Now they are not replying to my legit and generous emails. This were not expected from bookings.com