Yes.
If the item was shipped under the US Global Shipping Program, this is straightforward. You let the seller know the problem, then file an Item Not As Described dispute. Pitney Bowes, who run the GSP, refund the entire payment including the duty and sales taxes.
If the seller shipped directly, when you return it to her, you will have to call Canada Border Services Agency to get the duty and sales tax refunded. You will not be refunded the $10 CanadaPost service charge.
