ReLondon interview questions

I was invited to a first interview and they requested to prepare a presentation on how to introduce the topic of circular economy to companies and policy makers. And, in addition, to develop an assessment/case study in one hour. This for a first interview. The interview was average. They asked pretty standard questions and nothing that really stood out. The worst part is that after requesting a potential candidate to develop a presentation, and share the file with them on top of solving a case study, they never got back. It seemed they wanted unpaid work and get away with it.