Probably the same issue I am having. Recieved the message "The code you entered did not affect your order. Please note, codes may only be valid for certain items or in certain conditions."
There nothing in the T&C's preventing it from working!
Well spotted. I tried it on a hard drive and it worked. However I need a charger. What's the point of offering a voucher with a mobile purchase that can't be used for accessories for it!?