All Newegg refurbished products state that they are not liable for any accessories that are missing. I read the reviews on the product and everyone stated they had received everything that normally comes with the board. I was just unlucky when I did not receive the audio card.
I just might have to. Asus support has not been very helpful in responding to my support request. They have to have a stock of these parts somewhere. They used to have a parts store online, but it seems to have changed and all they offer now is power supplies, mice and keyboards etc. I'll check eBay and see if I can locate a Xonar then.