Explained (to me) earlier in this thread.
Samsung has no legal obligation to unlock devices from 2016, the CRTC/CCTS rules were different back then.
Samsung has no legal obligation to anyone other than the original owner of the device. They aren't at all involved in aftermarket trades/deals/retail, they'd prefer you buy new Samsung instead, lol. Your options are basically buy an unlock code on ebay or get the original owner of the device to helo with free Samsung unlock.
I just tried this, they ask for bill of sale! I have a used phone and they will not support me.
Why not buy unlocked on eBay?