If the ebay listing said the item was located in Spain (if it's no longer listed, ebay should be able to check the old listing for you) you should be able to get the ebay seller to cover the import duties and any handling fees.
Open a dispute with ebay (you can get through on the phone to an Irish call centre if you phone at the right time - don't bother talking to the Philippines call centre - they're not able to deal with any but the most routine of requests) and explain the situation.
Ebay should be able to take the cost of the import duties and any handling charges from the seller's account and pass them to you.
But if the ebay listing said the seller was in Spain but the item would be sent from China and that buyers may be liable for import duty, you don't really have a leg to stand on.
That's why I only ever buy from ebay sellers who confirm, either by message or in their listings, that their stock is physically located within the EU.
Edit: if you can convince Customs that the item had already been imported into the EU (by the seller or some other importer) when you bought it, you wouldn't be liable for any import duty. However, that doesn't seem likely if the item was posted from China to you.