Okay, Let me tell you how to do the on account on the ship.
Go to Carnival web site
Click on Fun ship dollars
Buy whatever amount you want
They will ask for Name, address etc.
Instead of giving your address put on that line "On Board Credit"
On the second line of the address, put "Your room number" Please don't the words your room number but actually the number of your room.
You will receive an e-mail within a few hours that tells you it has been added to your On Board Credit.
Take this with you incase there is a question of having done this.
If you call them to do this, they will not. What has happened is that the computer is set up to receive, but the site does not show that. If you call it in, it will come up to them, as you see and they will not do anything other than what is on their screen.
My On board credit is paid for. I will actually probably get some of it back, because it is probably more than we will spend.
If this doesn't make sense, please laugh and then ask me again.