https://www.myus.com/
I have no idea who they are but I don't quite understand.
Are they charging you shipping-- that is putting your purchases on a truck and driving them across the border and up to your house?
Or are they charging import fees? Canadian duty and more usually Sales Taxes on imports over $20CDN( ~$16USD) which is the Canadian law.
And what if anything does this have to do with eBay?
EBay has the much detested and reviled Global Shipping Program, but that is run by Pitney Bowes (and charges Canadian duty and sales tax at point of purchase not on the doorstep)