May i ask what and WHY this "maintenance" has to take the whole day?! What could possibly take this long to "maintain"? It is a game with 300 players...
Instead of shutting down the game for hours and hours every week, maybe you could update it with new things... Like last time... It got pretty popular when you added a new contact and levels...
Use your time to make new contacts, levels, cars and guns... Maybe that would get people playing this game again...
Add 50 levels, make a few "reskinned-guns" and some completely new guns and cars... That cannot be that hard for game-developers... Come on.
Shutting it down like this for "maintenance" does NOT help...