Just Pigments review for Zonos Duty and Tax

'Been using it for a few months. Not really sure how the pricing goes. For Canadian shipment I often see a $13 advancement fee which I don't understand. Zonos replied to my inquiry it's a FedEx fee to advance pay the duties and taxes which makes no sense since those duties are paid by us up front or by customer on delivery. FedEx is unresponsive at this point. I have my doubts the app is valuable or not to my internal shipping operation.