Trying to giveaway Batman Arkham Origins DLC (New Millennium skin pack)

1) Setting a higher contributor level will lower the chance of people entering a giveaway for a DLC they already own
2) What do you mean ? Just send one, don't spam the support
3) I don't know

edit : I understood wrongly, I thought you gave away two copies and both winners had it. Disregard 2)

How do you even check if someone has a DLC?

The only thing you can do is to check if the winner already has the DLC.

People who enter and already have the DLC are the ones to blame, not you. Request another winner again

1) Setting a higher contributor level might lower your chances of having someone who already owns the dlc enter.
2) It really depends, when you request a reroll, it's just as random as the first time the giveaway ended.
3) They won't be pissed since they are fair people and they too are against those who enter for stuff they already have.

Reroll until you get someone who doesn't own it already, there is no other solution as this problem is on Steam's side and that's what causing Steamgifts to incorrectly detect that said person doesn't own the dlc already. Good luck.

All right, thanks for the help everyone. Managed to get a winner without the DLC on the 3rd try. I'm relatively new to this so i didn't want to screw up anything