I booked my Disney Cruise in June of 2012 and paid with my Disney Visa to get the onboard credit. I was keeping my card paid off every month for a couple months and then due to a family emergency started using it thinking it at least wouldn't have any interest for 6 months. I just reviewed my online statements and realized I've been paying interest on it since September. Did I misunderstand something? Did the 0% interest only apply to the cost of my vacation? I had to cancel the vacation due to medical reasons and I've turned that into insurance, so I wouldn't really expect to get the interest reimbursed at this point, just want to know if I was misunderstanding how it worked???