I purchased Fun Ship Dollars on line and had them applied as on board credit. I received an email confirming the transaction. After we boarded the ship, I went to the purser's desk and confirmed the amount of OBC. It was there and available for use that day. On the second or third day of our cruise, I received a confirmation of my Fun Ship Dollar purchases. The confirmation slips were left under my door.
On the last day of the cruise, I received a refund check for the unused OBC. I cashed the check at the purser's desk before we left the ship. (Just a tip-they will require a photo i.d. to cash any refund check.)