For those who were the first ones to take part in the event at its start, logging out and back in should resolve the issue.
To open the prize box, you’ll need to right-click and then target the ground to select a target destination for your item. It’s likely that if there are a lot of other players around, you’ll have a difficult time seeing your item, but it should be there.
While we want you to get foils, we don’t want your fun foiled. We’ll keep an eye out for any other issues in the meantime. These machines won’t be going away, so enjoy!