Ideo Digital interview questions

The process was fast. They require you to do a case study. The interviewer seemed to want to end his shift. He told me they were busy people who work with big brands, and they interview hundreds of people for the role. This was said after answering one question only. Before the questions started, they already seemed set on a person for the role. After all the questions, I was told they would provide feedback on how I did. I received a rejection letter with no feedback on how I did for the case study.