How do I refund a deposit to a customer and apply it to their invoice and leave their invoice open?

Hi contact109,

Thanks for joining us! QuickBooks Online is designed to make your invoicing process smooth and easy. I'll be happy to share more on this.

The Open status for an invoice in QuickBooks Online indicates that no payment or deposit is linked to the invoice. A partial payment on an invoice changes its status to Partial and a full payment to Paid. To learn more about invoice status in QuickBooks Online, check out this article: Track the status of your invoices in the QuickBooks Online app

While you can't apply a customer refund receipt to an invoice in the system, you can do so with a credit memo. Here's an article to show you how: Create and apply credit memos or delayed credits in QuickBooks Online

After applying a credit memo, the invoice's status won't stay Open. As discussed earlier, it could either switch to Partial or Paid depending on the amount applied to the invoice.

I hope this helps to clarify things for you. Feel free to stop by any time if you have more questions.