How to cancel an iTunes pre order via my iPhone?

Ok so I accidentally pre ordered the deluxe and standard version of 1D's new album. With ios 5 I would have gone to downloads and whatever I pre ordered would be there and I could cancel it. But with ios 7 there's nothing in my downloads, although when I search the album it clearly says pre ordered on both the albums. So how can I solve this with my iPhone and if that's not possible my laptop.. Thanks