I would've done the same thing. If they then refused to exchange it, then I'd sell it and keep the profits. Either way, I would've done the right thing, and my conscience would be clean.
I think the only reason you felt like and "idiot" is simply because such a level of honesty and integrity is so rare that someone "wise to the world" would've assumed it was a scam.
Good job for doing the right thing when it would've been so easy to not offer to correct their mistake!
!BBH
!DHEDGE
!hiqvote
@kunschj! Your Content Is Awesome so I just sent 1 $BBH (Bitcoin Backed Hive) to your account on behalf of @bulliontools. (5/20)
Customer service said this type of error has happened before. She said they have honest customers. It was definitely a mistake since the sku on the package was correct for what I ordered and different from the coin they sent.