Were you not at home from january until a few days ago? The parcel may have been sent back to the seller... Post office only keep parcels for two weeks, but usually you get a "postal card" as reminder that something is held for you at the post office.
Some items bought from Asia may take more than one month to reach you, but "november" is too far back...
On Paypal, the protection is valid for the first 45 days and on ebay, you can leave feedback for up to 60 days after transaction. Never pass these delays no matter what's happening or what the seller promise you.
Have you paid with your credit card through Paypal or through your linked bank accounts?
If paid with credit card, you can contact the security/fraud/protection dept of your credit card and request a chargeback.
Otherwise, there is nothing much you can do... Sometimes lost items finds his way back to your home.
**French : Vous semblez être francophone, vous pouvez également obtenir du support sur le forum francophone de la communauté eBay en changeant la langue d'affichage en haut à droite du drapeau canadien.**