Pregunta de entrevista de Optum

First round started with simple problem solving and Java Questions. Second round started with my project description. The question asked in second round is simply "Remove redundant transactions in the system" and the interviewer asked me to code this. I am trying to ask different use cases which are possible and he simply asked what you have not understood in the question and the question is straight forward. The question doesn't have clarity, head and tail at all. This is one of the worst interviews I had. If the interview is asking the candidate to code, the question should cover different set of use cases and if he still expecting the different set of use cases for question, he should start that he is expecting what ever use cases are possible and then he should ask to code. Please set the proper expectations before the interview.