I don't think you can really complain that they aren't using convenient 2FA because you don't have a smartphone. It's a pretty reasonable thing to require these days.
You didn't complain that the online shop itself required the use of a computer.
(And yes, I have a smartphone but that should not be a requirement neither. My computer should suffice).
> You didn't complain that the online shop itself required the use of a computer.
Obviously online shopping requires a computer. It would not make sense to complain about this (though if I had to be a bit pedantic, the computer does not have to be mine. I don't need to own a computer).
At the moment the situation is workable for someone not having a smartphone, so, fine, but I hope it stays this way.