You can get your card number in-person or by telephone. However, if the reason you need the number is because you've lost your card, both options will result in cancelling your old account and setting up a new one with a different number. At the store, you'll need to visit a service desk or cash register and request a card number look-up. You'll need to show the rep valid photo identification, such as a driver's license, along with your telephone number. Otherwise, call 800-917-7700 for assistance. A representative will first verify your identity, such as by asking for your social security number, contact information or PIN -- personal identification -- number. The rep can either retrieve the card number or order a new card.