It's pretty simple. That part of the FAQ with the tree option is directed and the giveaway creator: Either they provide you with a key that you can redeem in your region - since they didn't properly setup the region restrictions, or you give "Not Received" feedback one week after the giveaway has ended. Should they ask you for permission to delete the giveaway instead of giving you a key that works for you to ged rid of the negative feedback on their giveaway, then it is completely up to you do decide to make them "guilt free" by letting them delete the giveaway to get rid of the negative review or to deny the request and leave it with the Not Received review, since they - after all - have not delivered the gift. But for that to happen they should first approach and ask you about it, since you have already informed them over two days ago that you were not able to activate the key. However you decide, you are not obligated to justify your decision. Sure in most cases users would allow deletion, but there certainly are many cases were not allowing deletion make quite a lot of sense as well.
As the winner you've done your duty 2 days ago by letting them know. It's not on you to run after the giveaway creator. You can just give feedback if they ignore the information you've given them and move on with your life.
I would also assume that if you simply do nothing for the next 7-8 hours about it, then this issue will resolve itself - but I cannot give you any more info regarding that since it is moderation related. So it's up to you if you keep running after the giveaway creator when the onus has been on them for the past two days and they've decided to ignore it or to sit back and just wait what happens (and give negative feedback should for some reason nothing happen).

Have a nice day - and a good start into the new year.