I think (!) there is a way of syncing an out-of-sync card on the Planet Calypso website! Maybe you can have a look there.
Edit: I checked their FAQ. You can resync in the game itself, actually. (But what John suggested works too!)
"Due to security reasons, you only have three attempts before your Gold Card becomes unsynchronized with the verification system. You will then be asked to resynchronize the Gold Card. By following the normal login process, a new window will appear that requests you to enter two consecutive Security Codes in order to resynchronize with the verification system.
If you fail to synchronize your Gold Card, please generate two consecutive Security Codes with your Gold Card and add these in a Support Case. Please do NOT generate any further codes until the support staff has confirmed that your Gold Card is synchronized."