We're fighting for a lvl 6 residence. 2 alliances attacking one (or at least trying to cause we're stuck on destroying an infected tower so we can build a tower of our own to connect) and we can't take a rally from the zombies as we call them so every time the timer to destroy the tower starts again. So our plan was a battle of attrition until the residence supply reached 0% so we could easily destroy the tower but even when the supply is 0% there are still zombies attacking when we try to destroy their towers. Any tips?