Cognizant — cognizant offer letter not received for interview on 29th sep 2018 at sb road pune

Address: 411057

I attended an interview at icc tech towers, sb road pune on 29 september 2018 (Saturday) for ios developer role in cognizant and cleared all the rounds.in the end, hr informed me that i will receive my offer letter in a week but i haven't received yet. Meanwhile, i received an email "interview status as select" from cognizant talent acquisition team on october 04 2018. After that, i haven't received any updates.
Kindly let me know sir what is the status of my offer letter.