Zoondia Software Engineer Trainee(Java) interview questions

I had my interview with Zoondia and I cleared all my rounds. At that time the HR told me that I was confirmed and she would send the offer letter within a few days. Then I had been waiting for about 1 and half month, but she didn't send me the offer letter. They conducted another drive for the same post within this time. Then I contacted her by phone. She said they had already appointed someone. I asked her the reason for not sending my offer letter. Then she became rude. This is my experience from zoondia. About the selection process...there were three rounds. 1. Aptitude test 2.Technical Interview 3.HR Interview