Did you go to the eBay Resolution Centre at the bottom of this page and open an Item Not As Described Dispute?
Did you return the item to the seller with tracking?
Did you act within 30 days of purchase?
If you tried to open a Dispute but the deadline had passed, did you go to your Paypal account and open an Item Not As Described Dispute in the Resolution Centre at the left side of the page?
Did you act within 180 days of purchase?
If you passed the deadlines for both eBay and Paypal, did you go to the credit card I hope you back your PP account with (PP is just a useful mediator), phone the 1-800 number on the back of the card and ask about a chargeback.
If you have not, do so.
Then let us know the results.
Tip: Do NOT allow the seller to promise a replacement. It will be no better than the original and arrival, if any, will take you past the deadlines.
Tip: Do NOT close the Dispute until the money is back in your hands. This takes seconds after the Dispute is decided in your favour.