Perfect timing for this thread. I'm going through this hell now. Cancelled two tickets in April.
In July when I was on the phone they said I had an unpaid balance for the change fees. But I know I paid them. So they gave me a fax number to send in my CC statement which I did. Then I called them a couple of weeks later to confirm and all was well.
Then two days ago I get an email about the unpaid balance again. I thought maybe it was for something else. Nope! Same fees as before. They now have no record of me sending them anything. Now I have to waste my time and send them the same documents again.