I live in Canada and have had a lot of stuffed shipped here from the US. My first choice for shipping (and the cheapest) is the USPS, next is Fedex and last is UPS. I always get a bill from UPS after the fact wanting more money (for fees, brokerage, etc). I have called and asked them for an explanation and they have never been able to give me a straight answer. I just don't pay them, and they go away, so I assume it's some bogus charge. If it wasn't, I'm sure they would pursue payment.
Aways ship USPS to Canada, if possible. If not then use Fedex. They don't send another bill afterwards.