Cognizant Technology Solutions — cognizant offer letter not released after getting selected

Address: Pune, Maharashtra, 411014

I had attended interview at cognizant on 09th june 2018 for informatica developer. Completed all rounds including hr. Hr told me i can expect my offer letter in a week or two week. Poc was nihar shah. I am not understanding why cognizant is keeping drive at every 2 week of spam. The one those have been selected, they are not releasing offer letter for them. It's not only the case with me. There are many those are facing same issue.