The application and interface is very easy to use. I am an occasional user, I have only sent 6 faxes. My issue is that when you click send, you log into your itunes account to pay. Then it goes back to the application and should send. I have yet to have it actually send it that first time though. I always have to close the application, and relaunch it and go to the activity tab to finally resend and get it to go. I havent ever been charged twice, it is just an annoyance and inconvenience.
ATXBrandon about Send & Receive Fax App- iFax, v2.14