RipeMetrics interview questions

After scheduling the phone interview on Calendly, they asked you to call them when the time arrived. The day before the interview day, I received an email sent by the Calendly system saying that my interview was cancelled. When I was super confused, another email came asking if it was okay to re-arrange our interview to a later time, after 5pm. I replied the CEO saying it worked for me and asking if we were going to have the phone call at 5pm, or if 5:30 worked better for him. No response. On the interview day, I sent another email when it was 1 or 2 hours before 5pm, wanting to confirm if we were going to do the interview at 5pm. Still, no response. So, I called him when it was a little after 5, asking him if it was a good time to have an interview. The interview process was pretty normal. I introduced myself. He asked me if I was aware that it was an UNPAID internship. I said yes. There was time for me to ask questions. At last, he told me that there would be a design challenge. It needed to be done in a week. Detail and other materials will be sent to my email address. Since the design challenge was a feature of their real product, I did not want to just send them my file as there were so many companies using "design challenges" to gain free design services. I sent an email telling them that I had completed my design challenge, and asking them when was a good time to present. THEY NEVER REPLY. In conclusion, this company wasted a week of my life doing their design challenge.