Redbubble Product Designer interview questions

The recruiting process required multiple phone conversations, interview in the office, design challenge at home and the last stage was a 90min session that included cultural interview (where the guys I spoke with had nothing prepared), discussion with product managers & pairing with a developer. The design challenge was misleading, on the instructions was very clear they wanted to see your process, how you approach design (in 3 hours) but my experience was that all they evaluated was the visual design and the process you followed was less relevant. After a 90 min session where everything went really smooth, I was told that I would hear back from them in a couple of days. It took 1 month for me to get some sort of answer and were just a couple of sentences telling me that I didn't make it. I had no expectations because I am considering multiple roles, I have a couple of offers and I wasn't set on anything, I just found this process particularly unprofessional and a waste of time.