In short, there was no stay to review. I booked a room with Collin in Washington DC and I informed him that I'd be arriving to check in between 10-11 pm on November 11. At 5:39 pm on November 11, Collin informed me that another guest was going to extend their stay at the room I had reserved. He said he had another room for me at another address. I told him that I was not interested in staying in a room other than the one I had booked and that I expected a full refund. I have not heard from him since the 11th and I do not see any refund on my credit card statement.
I did not realize that, once a reservation was made, it was even possible for an AirBnb host to "extend" a current guest, essentially voiding the reservation of the incoming guest. Knowing this, I will be very reluctant to use AirBnB in the future.