I think I just made a big mistake and I don't know what to do about it

[monac_mar]

I've had this listing up here for a while http://www.ebay.com/itm/121597990637?ssPageName=STRK:MESOX:IT&_trksid=p3984.m1559.l2649 . I'm selling a code for a game, and I describe that after someone buys it, I will send them the code in an email. Today, someone bought one of my codes, and as I googled how to send digital codes through Ebay, I discovered that apparently this is a big NO. So now, I don't know what to do. Do I cancel the sale? Do I email the guy telling him I have to send him the code through mail? I just don't want to get penalized by Ebay or Paypal.