Cognizant Technology — Delay in releasing offer letter

I had 2 rounds of interview on 23rd and 29th June. On 6th of July I got a call from HR and salary negotiation was completed and HR confirmed the offer letter will be released in 2 days.Post discussion CIS document was filled and sent to Priyadarshini.[protected]@cognizant.com.

After 6th July I didn't get any update via mail or call from HR and I tried replying to mail id but no response . Suddenly on 15th July I got call from another HR for scheduling next round with senior manager . Interview completed as scheduled and still no reply from HR about next process.