If you have received a CustomCat Charge fail error email, this could mean 1 of 2 things.
1. The card on file for your account didn't successfully charge your subscription charge
2. The card on file for your store didn't successfully process an order charge
When this occurs, you will need to go into CustomCat and adjust the following settings.
For your account:
Simply go to Settings > Scroll down to Primary Payment Method and adjust accordingly
For your store:
Go to Settings > Select Store
Select the store that had the error stated in the email
Scroll down to Store Payment and fix accordingly
Now, if the payment information on file is valid and you still received this email, either attempt to process the order again in your Orders queue or contact your bank and make sure that CustomCat charge get approved.