Redesigning Checkout Error Handling Using the Prevention Hierarchy

A checkout flow currently works like this: a user fills in a credit card number, expiration date, and CVV in three plain text fields with no formatting or validation, clicks "Pay," waits several seconds, and only then sees a red banner reading "Payment failed." There's no indication of which field was wrong or why.

1. Using the error-prevention-over-recovery hierarchy, identify which tier this flow currently sits at, and why.
2. Redesign the flow to move it up the hierarchy, being specific about what changes at each field.
3. Is it realistic to fully eliminate the possibility of a failed payment at checkout? Explain what tier represents the practical ceiling here, and why full prevention isn't achievable for this particular action.