The customer has a credit from an overpayment. A refund check was issued as indicated in the video. The customer's account is showing a credit amount in overdue column?

Good morning, @userk-sweeney.

Thanks for reaching out to the QuickBooks Community. I hope you're having a great day so far. 

Typically, unapplied credit memos will show as overdue in QuickBooks Online. You'll have to apply the credit to your customer’s open invoices, so it doesn't show Overdue in the Sales menu. To apply a credit memo to the open invoices, follow the steps below:

1. Click Sales from the left pane.
2. Select Customers and click the customer’s name.
3. Locate the invoice you want to apply the credit to and click Receive Payment.
4. Enter the necessary information on the Receive Payment window.
5. In the Outstanding Transactions section, make sure that the correct invoice is selected.
6. Click Save and close.

You can also turn on the credit memo auto-apply feature. This feature automatically applies credit memos to customers' balances or open invoices. 

Here's how:

1. Go to the Gear icon.
2. Click Account and Settings then tap the Advanced tab.
3. Select Edit in the Automation section.
4. Click Automatically apply credits.
5. Hit Save, then Done.

If you want to turn off this feature, go to the Automation setting again and tap the button beside Automatically Apply credits.

The steps above will help you apply the credit to your customer’s open invoices. For your reference, feel free to check out this article: Apply a credit memo, credit or refund to a customer.

Please don't hesitate to let me know if you have any additional questions or concerns. Have a good one!