I booked and needed to cancel due to emergency surgery. They told me after sending Dr. Note and Licence they would cancel and rebook. One week later and nothing. I was on the phone with them every day. Every day the same excuse. Please call back tomorrow. I finally booked a new flight with United directly. I checked with Better Business Bureau and found the following. They are fraudulent. Don't use them:
http://thechronicleherald.ca/business/*******-p.e.i.-company-justfly.com-draws-bbbs-attention