Cognizant — did not receive offer letter, interview date was 15th april, bagmane tech park, bangalore

Address: 560076

I have attended interview on 15th april cleared the interview and hr discussion. I recieved an email from cognizant for photo upload on 17th april and then an email of confirmation from cognizant that i have cleared all the rounds of interview on 26th april and then i did not hear anything form them. I tried to get answer from an hr from whom i got the call letter through email but she did not respond. There was no phone contact given. It feels like wasted a whole today for the process of multiple round of interviews.