What should I do if my Apple Watch is lost or stolen?
You should contact us on 13 25 85 to request that your card be disabled for use with Apple Pay. You should also go to iCloud.com and remove your card from Apple Watch. If you find your Apple Watch you can add your card back by following the same steps you went through when you set the card up with Apple Pay originally.
For more information on how to get help if your device is lost or stolen click here.