I have a customer who submitted an invoice twice by mistake and QB is attempting to draw the same payment twice. Is there any advice out there to fix that?

Let's setting thing out so you'll have a correct data in QuickBooks Online, halehomeskc.

If you have created and sent the invoice twice, I'd recommend deleting the duplicate one:

1. Open the duplicate invoice.
2. Click More at the bottom and select Delete.
3. Select Yes to confirm the action.

Then, you can ask your customer to ignore the duplicate invoice they received.

If the customer already paid the two invoices, I'd still recommend deleting the duplicate one. After that, let's record the overpayment as a credit memo.

1. Click + New in the upper-left corner and select Credit memo or Give credit.
2. Select the customer's name in the Customer field.
3. Enter the credit memo details.
   Tip: You can create a custom credit service item so you can quickly add it to credit memos as a single line item.
4. Select Save and close.

This credit memo can be applied to the customer's future invoices. You can also use this link for reference: Create and apply credit memos or delayed credits in QuickBooks Online.

If the customer asks for a refund, you can follow the steps under the Refund a customer's overpayment or credit section of this article: Record a customer refund in QuickBooks Online.

Keep us posted if you have additional queries regarding the process. Have a great day!