@etceterapatterns what was the cost of the pattern? They were probably charged VAT & Royal Mail collection fee, not duty, and that starts at around 15GBP, as I recall. It's a very low threshold. The VAT is the same as what they would pay if they bought it locally, but just as in Canada, it is the collection fee that stings for a low cost item. (Like most Canadians, UK residents often confuse these various charges)
Customs might be due if the item was made in certain countries; search for UK trade agreements.
If they think the charge is wrong, they will have to dispute it, not you. You could help them by sending them the links, but since you weren't the one charged, you can't do it for them.
I would not refund the shipping fee, as my policies and my automated note to the buyer on the transaction mail state that "You may need to pay customs, duties or taxes on your purchase in your jurisdiction (outside of Canada and the US)." In the rare cases I get a complaint, I send a super-sympathetic message explaining their very low threshold & commiserate that it is similar in Canada, then give them whatever links they need.
