Cognizant — Delay offer letter from cognizant

Address:

Bangalore

I had given 2rounds of technical interview and had completed HR round as well. In the HR round there was assurance of offer letter within 2days. After that I waited for a week and again asked for 2 more technical rounds for another project and after that documents were taken. Now it is been 3weeks i haven't received any update and no response for the calls. Kindly update on the status.