how do you know that he got it refurbished, how do you even know what he paid for it? I think that what he is asking for it is reasonable based on what information he gave us. If you think that it may be refurbished, your post may have been better stated:
$375 if refurbished, is it?
$600 if slightly used.
And he posted that it came from ebay after you made your lowball offer.