Optum Senior Data Analyst interview questions

Interview took three rounds of 30 minutes minimum. The interview was done in 2 days and then got the HR call. They offered me nice CTC and HR told me to send me the offer letter later. After that I chased for offer letter from HR and she was unable to get the approval for that salary, she told she will be providing the salary offered next day. Again next day the same story got repeated and was unable to offer that package as her recruiter told that I am not eligible for that package , then why they offered.