UPS makes 6X as much as tax paid to punt an envelope over the border.
With the shipping they charge, it's almost 50% extra on the cost of the order. In comparison, I shipped US$9500 of solar batteries across the border last month and paid $170 to a reputable broker that actually had to do some work.
Last time I had to deal with them the sender PREPAID all the customs fees, and they still charged me literally a total of 100% the value of the item! I've been fighting with them for over two months to get a refund.
contacting companies to tell them they lost a customer
I've done this and actually had one get back to me saying they adjusted their carriers and try again. My next orders went to them and I let them know that was why.