Things happen and we know you won't be able to deliver content for every game you get. This is why we have the three key quota, to give you some breathing room when you can't cover a game for whatever reason.
In order to refresh your quota all you need to do is make a delivery on another game you've received.
If you're unable to deliver content due to an issue with the game itself (a major bug for example) then we recommend emailing the publisher so they can try to fix it.
You can archive any offers you have that you won't be able to deliver on. This won't reset your quota, but it will remove them from your dashboard.