Vendor Payment adjustment with Old Outstandings

Scenario:

Vendor is paid against an Invoice. Now Vendor is cleared for that Invoice. After few months, during some testing of the manufactured product it was found the item supplied by the Vendor is rejected. Now that item is suppose to return to Vendor. But payment is already done for that item purchase. Hence I want to adjust that amount lying with Vendor for some other Invoices from that Vendor (preferably the oldest bills). Because, when the vendor is paid for other bills, we generally refer the Ageing Report as to which amount is outstanding as oldest and we make payments against the oldest bills. Now how do we know that this vendor has already got some money paid by us, and that has to be adjusted in the next payment or other bills outstanding. The volume of business is huge, hence tracking every transaction is not possible.

Can you suggest, what can be best process?