Solution

You will need to configure the Vendor Details as follows:

1. Go to Administration >> Vendors and click Get Data
2. Click on to edit the Vendor you want to configure the Invoices Report for
3. Click on the Other Settings tab
4. Tick Show Paid Amounts on the Invoice Report?

5. Locate the invoice you want to see the payments for
6. Click on to view the Invoice Report

NB: If the Invoice has been reassigned, two Invoice Reports will be shown, one for the original debtor and another one for the new debtor.

For more information see: How to Reassign an Invoice to a New Debtor