Well I'm not familiar with FYE (I had to Google it), so I don't know how significant they are as a merchant. If they are a major retailer in your area then they should not be selling used items, unless they've been labeled as "refurbished" or as being 'previously sold." It really all depends on the store's policy... whether or not they're selling new merchandise guaranteed against defects, or whether they're advertising the sale of used items "as is."
There's an old saying... "If it sounds too good to be true, it probably is"
However, I think you'd be foolish not to at least try to return (or exchange) them. Some stores would much rather just give in to you to get you out of their hair, rather than putting up with you for giving them hell.
If all else fails, learning a huge lesson that can last a lifetime for only fifty bucks isn't all bad, in my opinion.