Bought a cat-back exhaust for my Jeep on ebay a couple days ago. Got an email from the seller saying it was on backorder from the manufacturer so I can wait for it, get something else from them, or get my money refunded. That's fine but I look today and they are still trying to sell 19 more of these exhaust systems that don't exist. Is it common practice to sell things you don't really own? I understand they probably don't have the storage space for all these so they ship them directly from the manufacturer, but if they know they are on backorder, why don't they remove there ad?