Information on Updating Payment Plans
If you’ve missed a payment you can update your payment method from your “Orders” page by selecting “Update payment”. It’s not currently possible to update your payment details proactively, but there are no penalties for a missed payment.
Alternatively, you can select “Get help” from your “Orders” page, and then “I have an issue with my Protection Plan payment.”
You will need your Back Market User ID and password to update your payment method. The "Orders" link will take you to the Back Market log on page.