If you are selling on your website, then E-junkie won't let buyer sell a product that requires codes but is out of coded. Buyer will be shown an "out of stock" error.
However, if you are selling on eBay, then we don't have any control over the buying process (we only control the delivery), so if we your product is out of codes, we tell buyer that the code will be sent by the merchant.
We do inform you when you only have 5 codes left.