Welcome to the Community Forums, thanks very much for your post.
I'm very sorry for our delayed response, and to hear that you've been unable to access your Sky Sports channels from your additional mini box. It sounds like the Sky Sports codes may have not been applied to the additional box in error, but I can't say for sure until I look into the account.
I've popped you over a PM so I can take some more details. Please look at for my message over at the purple envelope.