In that case you'll need to contact a community manager for a refund of one of the purchases. It would be impossible to have two of the same game on steam in your library at the same time.
You can contact HairyGrenadehereor you can contact Oliohere, send either of them a message with your steam id, your identity email address and the issue at hand, in this case, you ordered twice, need a refund for one, and see if and what they can do about it. Sorry for the troubles you're going through