How do I unallocate a payment? I manually allocated and applied payment. No I don't find any record of it?

Thank you for joining the thread, @-holdtandbotha-c. I’ll provide you with the steps to unallocated the payments in QuickBooks Online (QBO).

To check the invoice and its payment, you can go to the customer’s profile then transaction list. This way, you can easily track your transactions specific for that customer.

We’re unable to remove an invoice payment that was paid through merchant service. However, we can delete the payment associated if it was manually created and applied to the invoice.

Here’s how: 

1. Click the 1 payment made link in the upper-right hand corner of the affected invoice. This is just below the PAID status. 
2. Click the date of the payment.
3. Once the payment is opened, click More at the bottom and select Delete.
4. Tap Yes. 

I've added some snippets below for your visual reference:

I also recommend consulting your accountant so you can be guided with the changes. This way, we can ensure your books are accurate.

You'll want to run the Invoices and Received Payments report. It keeps track of all payments you've received as well as the invoices that accompany them. You can select the Reports menu and search for Invoices and Received Payments.

I'm adding this article to learn more about receiving payments and applying for credits in QuickBooks Online:

• Record invoice payments in QuickBooks Online
• Handle a customer credit or overpayment in QuickBooks Online

Feel free to add a reply if you have further concerns with your sales transactions. I’ll be right here to assist you. Keep safe.