We're sorry to hear that! If you want a refund because of a technical issue you are having, please contact our support team. We would love to help you.
If you want a refund for a different reason, we do not have control over the stores where our games are sold, so you will need to contact each platform for assistance.
STEAM : Please contact Valve Support directly for assistance. Here is some more info about Steam's refund policy.
XBOX LIVE ARCADE: Please contact Microsoft. You can read their refund policy here.
PLAYSTATION NETWORK: Please contact Sony. You can read their refund policy here.
Best of luck in every gaming thing you do!