If your payment failed, there will be a banner displayed at the top of your account.
There are a couple of ways to update your payment method:
You can select the "update your billing details" hyperlink from the banner OR
You can select Payment Method from the accounts page here.
Once you reach the Billing Details page, you will be able to enter your card details, and press Update Card to update the card. Please note that this should trigger a payment attempt if the last payment attempt failed:
Important: If you receive an error that the bank declined payment, you may need to contact your bank. If you have already contacted your bank in regards to this error, don't hesitate to contact Motion Array support from the chat bubble on our site, or from here.