To be sure it's a steam key and not a gift. You still want me to ask support for a reroll? Also why did you mark it as received? If you clicked on received by accident you can remove that by clicking on received another time.

I've asked support for a reroll.

You don't have to do anything. I made a support ticket and a support member will do that. Once the reroll is done the giveaway will disappear from your won list.