I had a real difficult time cancelling a flight recently.
I have cancelled flights before and recently used those credits to book a series of other flights. When it came time to unfortunately cancel a flight this past Monday I couldn't do it online... the customer service rep told me since I used my jet blue credit and not a credit card I couldn't modify or cancel my flight online. Not that the $5 dollar difference really matter in this case but I was trying to tell her that before any money appeared in my jet blue credit I used my jet blue credit card to pay for the tickets.
She wouldn't budge.
--Russ