I don't have any problems with giveaway. I changed my mind about game + I got problems in RL before I was able to exit from giveaway.
So I decide it would be better to give it to another user who will be able to enjoy and will enjoy it more than me.
I made a ticket to support with ask for reroll. I don't know how many time it'll take but corresponding tickets from giveway creators usually get response fast. (Support -> Create a new ticket -> Request new winner -> Winner rejected gift).
I'm very sorry I made this discomfort for you and support.

Try again.