We had the same thing happen on our March, and May cruises. Use your sail & sign card in the slot machine, set up an account with a 4 digit pin number. You will charge monies to your room/account and play on that money. When through playing cash out on the machine and move to another and do the same or, then take card to casino cage and get cash from your casino account(your on-board account and casino accountare different). If you don't charge more to your room than you have OBC you won't have a bill at the end of your cruise, and maybe some OBC back as cash if your lucky.