First ask the seller for a refund. If they are anything less than TOTALLY HELPFUL, than you can file a "item not as described" complaint which GUARANTEES eBay will refund your money. Furthermore, eBay now holds the sellers money for about 2 weeks before releasing funds to the seller. SO, it's entirely possible that eBay will refund your money.
I always like to give the seller benefit of the doubt. AS A SELLER, I really appreciate the chance to fix problems before the seller files a complaint. I BEND OVER BACKWARDS for my buyers. I would hope others do the same.
You will likely have to return the item (which is unfortunate as it will likely be resold to another unassuming buyer) But if you take action ASAP, you will et your $$ back.
GOOD LUCK! (AND SORRY)