Cognizant — offer letter not received - cts pune, 15 dec, 2018

Address:

Pune, Maharashtra, 411057

I was interviewed on 15th dec 2018 at hinjewadi, pune for sap abap developer (Associate projects) role in cognizant.
I cleared all the rounds and including hr round. They made me fill a form with all my details on the same day.
Hr told me that with in 10 to 15 days i can expect the offer letter.
Its been more than a month now and i have not received any reply from them.