https://docs.google.com/document/d/1tbJLECLdYiaBuFGnFIqz-8pbdePEc7h-cbuPEvqmqjs/edit
Rather than chasing with customer/sales person, we will just create the credit invoice.
THIS APPLIES TO ALL PAYMENT METHODS.
HOW TO CREATE A CREDIT INVOICE
Open the invoice that was short paid, click on CREDIT go to ITEMS tab
Tick the item, do not tick RESTOCK
ENTER THE AMOUNT you need to credit (the difference, it will calculate itself)
Reason is INVOICE KEYING ERROR
Click OK then SAVE & EXIT
Then SAVE
You will see that the invoice has an updated amount and you can open it to see the credit note