Your question could be complicated, because it could fall under many different categories for Customs purposes. First of all, is it an original art print? "Original engravings, prints and lithographs" means impressions produced directly, in black and white or in colour, (can be retouched) of one or of several plates wholly executed by hand by the artist, irrespective of the process or of the material employed by him but excluding any mechanical or photomechanical process. The key here is that the plates or stones must be executed entirely by hand by the artist. These are DUTY FREE under heading 9702.
Now apply the North American Free Trade Agreement, according to which there is no duty to be paid if the goods are for personal use and marked as made in the United States, Canada or Mexico, OR not marked or labelled to indicate that they were made anywhere other than in these 3 countries. If your print doesn't qualify as an original work of art, does it qualify under NAFTA?
Normally, clearance value is the invoice value, however, Customs officials may revalue any article if they think it is undervalued or falsely declared. Putting an appraised value on a piece of art probably is not a good idea, since this is subjective, and the market value is usually what an item attracts on an open market. An appraisal can come in handy IF an item is reassessed by Customs at a higher amount than the appraisal. In this case, an appeal could be made, and the appraisal can then be produced . This may or may not work in the importer's favour.
Then there is the matter of which form was used by the exporter. If entering works of art commercially at a land border and the value is under $2500, there is a particular form required. If the item is valued over $2500 formal entry through a Customs Broker and ACE manifest is required. Yours is considered a commercial entry, because it was not a personal importation at the border. If the appraised value used was over $2500, then the seller possibly paid for a Customs Broker. If so, the $800 would be their fees plus applicable taxes (GST/HST). Ask yourself, is this his problem or yours? Did the seller indicate he ships to Canada? Was there any information in the listing about possible export/import fees? Were shipping costs clearly included in the listing?
Take the advice given of not doing anything, including contacting the seller, until you know more of the situation. Do you have the paperwork completed by the seller or his shipper? Can you see if any duties and taxes were assessed? Did the shipper pre-clear in the US? Was this a GSP shipment? And as you were advised, generally speaking eBay does not support additional charges from the seller after delivery.
