Thanks for getting back here in the thread, Casey.

Yes. There's a way to change the payment method and uncheck the box for accepting credit card payments inside QuickBooks Desktop (QBDT). I'll gladly walk you through the process to get you going. To begin, here's how:

1. Access your QuickBooks Desktop company.
2. Go to the Customers page, and then locate the customer you'd like to modify the payment method.
3. Click the Pencil icon beside the Attachment icon inside the Customer Information.
4. Go to the Payment Settings and then in the Preferred Payment Method section, click the Dropdown arrow and select the correct payment method for that specific customer.
5. In the Online Payments section, uncheck the box beside the Credit Card or Bank Transfer.
6. Once done, click the OK button to save your current setting for that customer.

For visual reference, see the screenshot that I've attached.

See this article for more information: Add, edit, or disable a credit card.

In addition, here's an article to help you manage invoice payments inside QBDT: Record an invoice payment.

It's been a pleasure to have you here today, Casey. In case you have a task that you'd like to accomplish inside QuickBooks. Feel free to mention me in the comment section below. Stay safe, and have a nice day!