We recently switched to a new payment partner to improve our purchase experience for our global users. As a result of this change, during checkout, you may need to re-enter your credit card.
Also, make sure to enter the same billing address as your credit card billing address to avoid declines. Check the screenshots below where it shows where to remove and then re-add the cards on the checkout page respectively:
Mobile Image 1, Image 2
In case you face any issues while removing, adding your card or with your purchase, please contact our support team through tickets here.