I have ran into this problem and it had to do with my address being a post office box # that both Samsung and my bank don't accept as being an address.
I live in the country and that has always been my address. I have had my order declined multiple times because of this and understand your frustration.
Last year Samsung started accepting pay pal and I have a confirmed paypal account and since then have been able to purchase using this with no problems.
They could at the very least contact you to let you know that your order was not accepted but don't seem to think they should have to.
Sorry for the inconvenience caused to you. Please check the direct message I sent you by following the below instructions and reply to us with the requested information. so we can look into it.
Log in to the web version ( https://r1.community.samsung.com/ ) of Samsung Members community Canada and click on the Message icon at the top right(Samsung Members) >> Inbox >> Reply to the DM(Direct Message).
I suggest you to contact online shopping live chat support so that they will help you to pre-order a Samsung device from the Samsung Canada website. They will help you with the available options.
Here is the link for online support: https://www.samsung.com/ca/support/contact/#onlinesupport