Cognizant — interview status on select but offer letter not received

I attended interview on 13th july 2019 on varalakshmi tech park in kandhanchavadi chennai for msbi technology. I got selected for the role. Had package discussion with hr and also hr promised that i would receive offer letter with in 8 working days. But i received one mail from cognizant-tag "cognizant interview status - select" on 18th july like below they mentioned

Greetings from cognizant! We are pleased to inform you that you have cleared the interviews held on 13-jul-19. Confirmation on your offer will be subject to the need for an additional interview / client interview / approval from the business unit. Please expect an update from your recruiter on the same at the earliest possible.

Please let me know as soon as possible about the status of offer letter...