"If you already sent, we can get in contact with him to arrange to get your cards back. If he doesn't respond in a week or so, then see about filing mail fraud."
I would like you to contact him for me, please. I was also trading with him and he probably received my end by now, so is it possible if you can get him to either send his end (which I prefer the most) or send my end back? If he doesn't respond by next Saturday can I file for mail fraud against him?