NIIT Limited interview questions

They started it by giving a test to be done from home, in which I flaired, later I had a telephonic round for which I was not given any feedback but just the next day I get an email stating a cognitive test to be completed. I finished the same with no response from HR, after 3 days when I called the HR she calmly said I was rejected in my telephonic round and the cognitive test. Why do you waste time of people if you don't want to hire and why to retest for the next level if you have already rejected a candidate. This has happened for Mumbai location.