For those who've gotten some to work, you're welcome.
Isn't it strange though that some posters CAN get them to work?
I wonder what Kobo's limiting here, maybe the amount of codes a person's used on their account?

Because we've proven they're not account or country specific. I don't know, and frankly, like I said, I can't be bothered with them anymore, way too much of a waste of time.
Glad some people got use out of some of them though.