Booking.com Software Engineer interview questions

I attended Booking.com Hackerrank assingment which has 4 questions and takes 75 min. Two weeks later, while I was abroad, I got an email from them. Email was starting with "congratulations" . They were requesting 25min HR interview.  I was abroad for vacation, on Monday morning I wrote my time frame according to the local time and I waited their call during the week.  On Friday I got called very early morning and eventually I missed the call. I replied back with email and mentioned that I am still interested in the role and that I will be back to my country next week, and again I wrote new available time frame according to my country's local time. After that Booking.com never called me back even though I sent a reminder email.  It is very time consuming process, I think there are too many candidates like me, it is like a lotery and very disappointing.