Where invoices have been credited, they should be stamped as 'credited' rather than paid.

This would prevent costly sales errors. When searching customer history staff see that a customer has bought a particular item because the invoice shows a paid stamp when in many instances the invoice has been credited, and NOT PAID. This has resulted in the same mistake being repeated time and again. Costly shipping out and back in, not to mention irate customers (if not a complete loss of customers), should prioritise this request.