Occasionally you will get an email or notification that your product order cannot be fulfilled by Amazon FBA.
Unfulfillable inventory is inventory that has become damaged, expired, or for some other reasons cannot be sold. When this occurs, Amazon sets the item as unfulfillable and you have (usually) 30 days to have the inventory returned or destroyed before Amazon does as they please with it.
The email will look something like this:
If you get an email like this then you will need to cancel the order on ebay and alert the customer as soon as possible