I've accidentally added payments to invoices that have not been paid

Welcome and thank you for posting in the Community, @tianihhill-gmail. It's my priority to help you today.

You can simply delete the payments by going to the Sales menu and opening the affected invoice. From there, click the More button to delete 

the payment. Let me show you how:

1. Go to the Sales menu then select All Sales.
2. Click the 1 payment linked in the upper-right hand corner of the affected invoice. This is just below the PAID status. 
3. Click the date of the payment.
4. Once the payment is opened, click More at the bottom and select Delete.
5. Click Yes. 

Then, the invoices will automatically be opened again. Please take note that deleting a transaction in QuickBooks Online can not be undone. To give you more insights on how receiving payments works in the system, please see this link: Learn how to receive and record the accounting for invoice payments.

You'll also want to run the Invoices and Received Payments report. It lists all payments you’ve received and the invoices that go with them. Just go to the Reports menu and type in Invoices and Received Payments in the search bar. 

You're always welcome to reply to this post if you have any additional questions or other concerns. I'll be around to provide further assistance. Have a nice day, @tianihhill-gmail.