I processed a payment via quickbooks, but feel the client called his card to have it declined. What should I do?

Hi there, teambailey. Thanks for joining the Community, it's a pleasure to have you here with us. I'll help you with this.

There's a wide variety of reasons why a card can decline. It could be over it's limit, expired, past due, or the information they provided you with might not be accurate. Sometimes the customer's bank won't specify why, and will only provide a generic decline. 

I'd initially recommend notifying your customer of what's happened, and that the amount is still owed to your company. Double check the card details with them to verify you're using the correct digits and billing information. If you're still unable to process the transaction successfully, ask your customer to reach out to their bank to confirm why this is occurring. If the issue persists after they've contacted their card issuer, you can request a different form of payment from the client.

Here's an informative article about this: Why is my customer's card declined?

I'll be here to help if you have any questions.