I think the problem is that the "picture" is not a photograph but an artist rendering. This rendering shows what parts are covered and what are not; it clearly does not show any cutouts for side buttons - this should be visible in either the front or back image.
They took a picture of the phone and shaded around it with an opaque image to show how the case would cover. The case is bigger then pictured, and has a completely different level of transparency. I see no disclaimer that this is an artists renderring.
This is misleading and i would dispute with your credit card company or paypal.
Samsung Captivate - rooted
iPhone - jailbroken