Cognizant — offer letter not received for interview on april 21st 2018 in st. joseph college

I was interviewed on 21st apr 2018 (In chennai), both technical and hr rounds are completed on same day and hr told they get back with in one week and you will offer letter soon.

Still am not receiving any confirmation mail.

Its been 4 weeks now and i have not received any reply from them.
Kindly let me know, what is the status of my offer letter.