It was a 4 stage process. I thought it was a decent experience and every one I interviewed with seemed nice and I 100% wanted to work with them. I got to the 4th stage but never interviewed. I sent numerous messages but was met with no response. It is not a problem to hire someone else. However, it is unfair to make a person create an entire technical document ready to present for a final stage and completely ghost them.
I think they should do a lot better with their communication. Additionally, don't let people waste their times on technical tasks if you know it will not see the light of day.