Murer Consultants interview questions

Was emailed to come in for an interview. Met with several people in a conference room. One cut it short. I was in for only 20 minutes. I figured that they were not interested. Yet, I was then asked to do a 4-hour writing assignment, which they emailed to me at a selected time. I turned it in on time and was told they would get back to me the following week. Never heard back. I think it is VERY unprofessional to not even send a rejection letter or email after a candidate devoted 4 hours of their time, not including the actual interview.