Hi .. Buyer is responsible. Has nothing to do with shipping and it is illegal for any seller to falsify items value. Perhaps send this link..
http://pages.ebay.ca/help/policies/encouraging-illegal-activity.html
Ebay will remove and negative feedback that references customs.
Your listings should contain a statement on responsibility to avoid issues..
"Import duties, taxes, and charges are not included in the item price or shipping cost. These charges are the buyer's responsibility"