Fiserv Team Lead interview questions

It was a complete day process with total of 4 rounds. First there was an written exam in which candidates were asked to design one sample problem which they provided. After that there were 2 rounds of technical round of around 1 hour each. Interviewer was asking questions mainly on current project. After that there was one objective type questions exam which was little bit difficult. At the last I was told that I have cleared all the rounds and HR will call me for further process. I got a call from HR in next 2-3 days who asked my some basic details and told me that he will be sharing the details with the business. After that he did not call me till now. They just wasted one day of a candidate and did not provide my offer letter to me even though I agreed on the salary package they decided to offer me.