Criteo Technical Solution Engineer interview questions

Interview process was easy. Answered all most all of the questions. Interviewers were friendly .But they don't have clear understanding why they are recruiting .Finally no response from HR at the end. They should be professional enough to say at-least "Not Selected" . We are spending our valuable time and energy for the interview and it is very bad if finally they dont bother to send one e-mail at-least. I felt very unprofessional!!