If someone declines a game take availability for that day away
If someone declines a game remove their availability for that day. Then you do not accidently send them the game again or another one.

We’re not in favor of automatically blocking availability, however, we have incorporated a new feature which will prompt officials immediately to close their availability for a day when they decline an assignment. To use the new feature, you’ll need to ensure the Availability Locking system (Feature #3) is set to either “Only if unaccepted” or “Never” in order to permit officials to immediately change their calendar when they decline an assignment. The decision to close their calendar will still be in the hands of the official themselves. Thanks for submitting an idea.