[GNC] How to use refunds or credit notes

[John Walker]

I have a situation where I have charged say$2 008 in an invoice. After 
posting, the customer correctly told me that the invoice should have 
been $2 000. The invoice has already been correctly paid at $2 000 and 
payment due date has already happened.

When processing the payment, I entered $8 in the refund and the invoice 
changed to $2 000 as one would expect. After processing the payment, I 
still had the $8 to process in the process payment window. How do I 
properly process this?

If I should have used a credit note, how do I do that?