Cognizant — false hope

Hi, i attended interview for senior process executive role on april 1st and cleared all rounds scored good in written and after all waiting from 10am-6:30pm they simple said no vacancy, i dont feel good at that time cause if they know that they dont have than why they are wasting our time? And said next time will consider you directly with only one screening and now again today i called them after getting job notification for same position having 10 vacancies in naukri, they said okay will see and we are not sure we have vacancies is that right way to be?