I know that this might sound weird, but could it be possible that you ordered it in your sleep?
I mean, people sleep walk, and certain sleep medications have side effects of people doing strage thing while asleep, so it's not unheard of to sleep shop.
Anyway, you can just refuse delivery, and you won't be charged a penny.
It's the simplest and easiest thing to do.
Just be sure to let CS know that you refused delivery on it, and that it's being sent back.