Credit/Refunds in Zoho inventory/books

Credit/Refunds in Zoho inventory/books

Hi Everyone, 

We are just starting Zoho Inventory/Books at the beginning of this month.  We are having a problem with returns/refund.  Credit memo's or refunds can only be given if an item is returned.  However, there are several times where a simple refund is needed or partial refund or the item was purchased at the end of last year where there isn't an item to return.  How do you all work around this?