Digital items are tricky for online sales.
Since the seller is apparently ignoring you (has it been a full 24 hours since you emailed him?) I would open an Item Not Received dispute in the Resolution Center at the bottom of this page.
The first suggestion is to contact the seller, but since you have done that, go on to Escalate to a Claim.
If the seller does not show that he has delivered the game to you, you will be refunded.
You can leave appropriate feedback for 60 days after purchase. The most effective FB is calm and factual. Do not mention the Dispute, that will get the FB pulled. Wait until the Dispute is played out before leaving FB.
