If you can not subscribe to any tool4seller plans successfully, especially if the payment failed. Please switch your credit card to try again. Or you can log in to your tool4seller, and enter the "My Order" page.
Find the failed order and you will click the "Confirm" button to complete the credit card security authentication on stripe so that you can subscribe to the plans.
More questions, welcome to contact us at support@messages.tool4seller.com.