Thanks.
I won this GA but i can't give a feedback.
Never had this problem before and i don't know why IG not give me the button as normaly.
Maybe a problem at their site, that solve by itself in X minutes or hours.
I will look tomorrow again into it and hope i am then able to give a feedback.
This was a "Guaranteed" giveaway, this means the game key was bought on IndieGala and given away directly instead of being revealed. You can only leave feedback on the "Non-Guaranteed" ones. From my understanding, if there is an issue with a "Guaranteed" key, you need to raise a ticket with support.
Edit:
There are three categories for giveaways, denoted by a colored bar under the the game picture
Reddish = Guaranteed giveaway hosted by IndieGala, could be single ticket or multi-entry
Blueish = Guaranteed giveaway, the game key was bought on IndieGala and directly given away, could be single ticket or multi-entry
Grayish = Non-Guaranteed giveaway, any giveaway where a key was entered during creation, always single ticket