[Sharkus]

It was ok on Wednesdsay. perhaps their servers are being heavily loaded?

Key things here. If the failure is at the purchase side of things then I believe it is a pottermore issue and not a Kobo issue as at this point Kobo isn't doing anything. It's the same purchase method for everyone. Once the purchase goes through and you link your account that's when Kobo comes into the equation, so if it's failing at the link stage, then it could be something on the Kobo side of things.