Complete this form and send it to Carnival. If your TA booked your trip, your TA needs to complete this.
FYI-make sure the info is exact or the claim will get denied and you will have to resubmit.
If you are missing info, it gets denied sooner than later. If you don't hear back right away, then it's probably being processed; it takes 2-4 days for a successful credit to be issued.