Cognizant Technology Solutions — Not getting offer letter and hr also not picking up the call

Hi Team,

I had given interview on 9th Oct 2021 and got hr call on 12th October for salary and all other discussion happened.After that I didn't got any updates and hr is not replying to my mails and he switched off the his cell phone as well..
Can anyone help me for the next steps?
Why they are wasting candidates time and all.
Let me know where I can raise the ticket and all for this issue.

Thanks