Cognizant — cancellation of process

Address: Hyderabad, Andhra Pradesh, 500073

Hi,
Me& my friends attended the interview in cognizant (Raheja mind space, madhapur) & we got selected in that health care process on 11th aug 2018 & today its 28th sep 2018, but still we didn't get a offer letter... And there is no confirmation mail from cognizant, and one of my friend rejected an offer letter from optum solutions company beacuse of this, he waited for offer letter from cognizant, and we are also not attended a single interview for 2months... But still there is no response from cognizant office
Please kindly solve our problem...