Here is my take on it. His type of scam is different, he'll give you playtime with the credit card, and then when he gets the keys, he'll call his credit card company and get it removed, which will in turn piss of Blizz, who will ban your ass. I'd make sure he gets you a gamecard, and that he gets you a gamecard first so you can make sure he isn't cheating you on the gamecard.
Also, glad to see my D2 Keys are going to good work

I can sell you more Madhoun, at a very cheap discounted price if you need more.