Cognizant Technology Solutions — Not received an offer letter after submitting documents

Hi All,

I has given technical round interview in CTS on 14th August 2021 for role informatica MDM developer. I received HR call for salary discussion and document submission on 17th August. I submitted the relevant documents as requested through mail. I had a discussion for salary and I was informed that I will receive an offer letter shorty but did not receive any update on the same.
I tried to call back on that number and followed up on mail as well. Did not get any response.

Will anyone please help me to whom should I contact? Also should I wait for the offer letter of not?