Over 99.9% of the time, when a member or customer attempts to charge a credit card on your website, the payment processes as it is designed to do, sales receipts or payments are created, and staff don't have to take manual action.
Should Novi not be able to connect to your payment processor's API connection, it is possible that a wrench can be temporarily thrown into that system.
Behind the Scenes
When Novi processes a transaction, the basic workflow is as follows:
Create the sales receipt with "pending payment" in the memo screen
Run the card through the payment processor
Replace "pending payment" with the payment ID
In more than 99.9% of cases, the "pending payment" is only on the transaction for a second or so. If transaction fails to process, we at least have that "pending payment" breadcrumb to indicate that there was an error.
Resolution
Should you determine that a sales receipt or payment has indeed not been funded, then you will want to take manual action. Actions could include the following:
Delete the sales receipt or payment that was not funded and re-run the workflow in Novi (register the member for the event, create the dues invoice, etc)
Manually run the customer's credit card through your payment processor and match it up to the sales receipt or payment