Similar story: I bought a racing game from Impulse because they listed the release date as like Sep, 24, 2009 so not being one up on racing games I figured sure, why not, I like racing games and the only way to buy a multiplayer racing game is to get in on the ground floor before the community drys up and blows away.
I loaded up the game, and went into multiplayer to find a deafening silence and absence of any other players. I went researching on the net to find out that the game had actually been released in 2007, and so I guess Stardock must have added their own release date of when the game was made available on Impulse. So I asked for a refund and sure enough in 2 days I got one. I was very pleased that I didn't have to go jumping through hoops or having to spend more time than normal to explain the situation. I simply told them the facts, they listened (read) and refunded the purchase price.
I've had to try to get refunds before from Direct2Drive and it was a nightmare and they refused and finally after going back and forth about 8 times in email they relinquished and were *kind* (cough, cough) enough to issue me a credit for a game that they clearly listed as having multiplayer, but which the publisher had long since shut off the multiplayer servers.
If Impulse would just get more games added in, I'd do more shopping here and far less over on steam.