Cognizant — iam complaining about offer letter

Address:

H.no.3-7-4,Indiranagar,karimnagar, Karimnagar, Andhra Pradesh, 505001

Ive attended interview at cognizant (Mindspace), madhapur, hyderabad.
As usual ive cleared my first round on 10 jan that was amcat test, and later i called for hr face to face on jan 13, i've cleared that round too, and then i got a mail on 15 jan for pho session will be on 16 jan, i've filled the application form, but i havnt got any mail from organization. When do i get my offer letter?