EBay charged my buyer for sales tax and announced to charge me too for PST/HST. IMHO selling and exporting to USA is free from Canadian sales tax. Please clarify

Sold https://www.ebay.ca/itm/276399503918 from Canada to USA. Who pays sales tax? | Selling

Sold https://www.ebay.ca/itm/276399503918 from Canada to USA. Who pays sales tax? | Selling | eBay Canada EN