I am confused - will what work? If they took your order and charged your credit card the vouchers should arrive at the address you gave. You will be getting a green plastic credit card like voucher which you will need to turn in at guest services when you get to WDW along with your photo ID which will have your street address I imagine. At that time they will issue the actual AP. This will match up to the address on your contract and ID so I would think everything should go smoothly. I am sure there are a lot of people who use PO Boxes to get their mail so don't think you will have a problem.