What is a Device Account Number and how is it different from my Card Account Number?
When you add cards to Fitbit Pay, a Device Account Number is created in place of your card number. This number is used when you make a payment with Fitbit Pay (or a refund of that payment) so that your card number isn't shared with the merchant and won’t appear on the receipt. Each time you add a card to Fitbit Pay, a new Device Account Number is created.
If you are using Fitbit Pay to obtain a refund, you may have to enter your physical card PIN number at the Contactless Pay terminal.