Came at me like it was super urgent and they were super keen, almost hot and heavy, then left me waiting in a holding pattern. Seems surprised that I thought it was a long time between communication from them.

Interview process is generally three rounds with one of the rounds being a case study, if you prepare this properly and deliver it in a concise way you should get through fine. I've seen many people carry on for too long and not articulate well so do a practice run to help you get through it well.