I think the seller was using the new Global Shipping Program.
Your seller got enough of the shipping fees you paid to send the parcel to Pitney Bowes in Kentucky.
The rest of your shipping fee went to Canada to pay duty and sales taxes as well as a $5 (approximately) processing fee to PB.
I do not understand the part about the address. Is that address on your eBay or Paypal account? Have you ever sent a present to a relative or friend who lives at that address ? (I still get my daughter's bank statements although she moved out nearly 20 years ago.)