How to waste someone time - Backend Developer Field Materials Employee Review

They wasted my precious time. They sent me a backend assignment, which I did, and I spent around 2 hours of my free time on it. Then, I was waiting for the interview. At the time and date of the interview, no one joined the call so I wrote to the person organizing the whole thing and he told me, that they "forgot" to mention that the role had been closed. At the very end, they told that they will do a review of the assignment, but the question is: what for? :D