Hello,
I recently bought a Wii U 8gb basic console. I downloaded the update and set it all up, and then I created a Nintendo Network ID and linked it to the Wii U. I believe it is also linked to my club Nintendo account, I am not sure really. Anyway, it was defective, the game pad wouldn't charge, something was wrong with the battery. I returned the Wii U and got a new one. I have updated it but I cannot link my Nintendo ID because it says it's already linked to another Wii U. Is there anything I can do to unlink my Nintendo ID from the Wii I returned to the store?