How do I apply a payment to an invoice previously written off?

Hi there, user95543.

It's nice to have you here in the Community. I can help you apply payment to an invoice that was previously written off.

To do this, you'll need to void the credit memo and the payment made for it so you can have the invoice back. 

Here's how:

1. Open the credit memo.
2. Scroll down and click More.
3. Click Void.
4. Click Yes then OK.

Once done, you can now apply the payment to the invoice using the Receive Payment option. Just open the invoice and click Receive payment button.

For a detailed steps on how to receive a payment for an invoice, please refer to this article: Record the invoice payment.

In case you need assistance from a live support in doing this, feel free to reach our QuickBooks Online Care Team.

Here's how:

1. Go to https://help.quickbooks.intuit.com/en_US/contact
2. Select  QuickBooks Online.
3. Select a category under “What can we help you with?”.
4. Scroll down the page, then click the Get Phone Number.

There you have it. If you need anything else, please feel free to come back and leave a comment below. Have a good one.