Well, this is pretty egregious and makes me rather happy I don't use them. From the looks of things you can also change the email associated with an order and send yourself the info all over again. This means for some things, like online services or say application licenses, you can resend the info to yourself and probably steal the actual customers product.
Additionally, I'm willing to bet quite a few of these people have used the listed email and last 4 for other things online and/or for verification of identify places.
Also, how is this PCI compliant?