Start with contacting the seller and trying to resolve the problem. The simplest resolution is returning the item for a full refund. The seller has the option of also refunding your return shipping if he agrees with your opinion. Use Confirmed Delivery, which is Expedited Parcel in North America.
If the seller is not helpful, you can go to a Paypal Dispute "Item Not As Described". You have only 45 days from the end of the listing for this.
You can leave Responses to feedback, both yours and the seller's, indefinitely.
If more time has passed than 45 days, you can go to your credit card for a chargeback.