Once your order is cancelled (due to the seller missing the deadline or other problem) you can't leave any seller feedback or reviews of service. Hence, only the good reviews of a seller are posted. This is a major drawback, as you can't get an honest idea of a sellers all-round performance.
Jimmygibbs did a good job on an eBook cover, but two months later when I asked him to do the paperback cover he missed the deadline, and did not incorporate any of my requests into the finished design. I had to use another cover. Very poor communication. Fiverr communication is difficult. Sometimes you have to logout and then login to reach a different part of their site.