If it proves to not be as described, arrives damaged or not at all your are covered by the Money Back Guarantee. If the Seller ignores you at that stage e-Bay will "step-in," refund you and then chase the Seller.
Incomplete descriptions are a pain and you never know if somebody is just lazy/careless or if they are hiding something. They may be perfectly decent and simply don't know much about the item. As for what I'd do in your place I can't say as it would depend exactly what the listing did and didn't say.
If it happens to be a Business Seller you have the legal right to return something within fourteen days for any reason, including simply not liking it. If it's isn't Not as Described, damaged &c you'd have to pay the return postage but again e-Bay would make sure you got your money. It depends how badly you want whatever it is and how much risk you feel is justified. For a common item I'd look elsewhere but if I was unlikely to find another, or another at the price, I'd be more inclined to chance it.
Cacas vendit.
