I appreciate your efforts in trying the steps provided by my colleagues above, @lvjt. Your dedication to resolving this issue is commendable.

As previously stated, deleting a customer's credit card from the Payments and Billing tab is currently unavailable. However, you can modify the information by editing the card number. This way, the system can no longer charge their card.

Here's how:

1. Click Sales in the left panel and choose Customers.
2. Select the customer name, then Edit.
3. Go to the Payment and Billing tab.
4. Choose the credit card number under the Preferred payment method field.
5. On the Credit Card Information window, click Add.
6. Change the following:
   • Credit card number: 4111-1111-1111-1111. This is a non-transacting test card number.
   • Expiration date: Any date in the future.

See this screenshot below as a reference.

You can check out more information in the article: Delete your customer's credit card number. This detailed guide offers two options for preventing charges to your customer's card and provides the necessary support.

Furthermore, you can check these articles whenever you have concerns about recording customer payments: 

• Record invoice payments in QuickBooks Online.
• Customize invoices, estimates, and sales receipts in QuickBooks Online.

Feel free to contact me if you need help managing your customers' credit card information. I'm here to assist you whenever you need it.