Re-rolled winner marked as not received, before I had the chance to send it.

If the winner has created giveaways themself in the past, best comment in one of those.

Edit: Just saw you already did this.

Sometimes. When I have someone who doesn't mark the giveaway, I'll post on the profile if I'm able, otherwise I'll send a friend request, a Steam chat message, AND an email. You never know what time of day they check any of these, or maybe they ignore chats but not emails, etc.

I do this on Day 6, which should be enough time for anybody to check to see if they've won anything on steamgifts. In your case, I'd do it all immediately.

Yeah I really feel there should be some type of notice. I had a re-roll once before, where a winner already had the dlc, and when the ticket was approved, the moderator commented on the ticket, so I saw a notification. With the previous winner on this giveaway having not accepted it for over a week, I got used to seeing that red "1" on the giveaways icon, so I realized it had been approved just by chance.