Cognizant Technology Solutions — Offer Letter Delay | Urgent

Hi, I am Prashast. I had given 2 rounds of interview, on 10th Nov, 2021 Technical Interview and on 15th Nov, 2021 HR. During the HR discussion I was informed that I can expect the offer letter within 15 days post submitting the candidate information sheet and pay slips etc. (which I already did on the same day). It's been 25 days and I haven't heard back from Cognizant Team. The HR is neither picking the call nor replying to emails.

Please help me in getting the offer letter.

Thanks in advance.