Similar situation with FedEx.
Ordered a laser from Laserglow, $45 was tacked on, on the way in, from the broker.
Sent it back for replacement a week later, $45 again, even though marked "return for repair" per Laserglow's instructions (exactly) and I even had a FedEx person on the phone tell me how I should be doing it.
If you ship internationally, you'll get charged brokerage and customs fees. What you mark on it doesn't matter. Sometimes you get lucky and you don't. Most of the time, i'd simply count on it.
The reason is, - they can charge it, and when you call, FedEx can say "It's customs! There's nothing you can do about it! We can't call Canada and say 'we want this guy's money back'!"
Thing is, yeah, a tarriff can happen, but part of this is purely brokerage fees to figure out / collect the tarriff.
I fought with FedEx for a long time to try to get my money back on the 'taxed in taxed out' one-week laser. It went nowhere.