invoices and that doesn't make her angry, just have them keep going. The value of having a happy neighbor and a well kept neighborhood is worth far more than starting a battle over a few hundred dollars.
Sure they may never see that money, but you'll see better value out of that rather than deciding to fight for that money. I realize nobody wants to be seen as a push over, but this just doesn't sound like a fight worth fighting. Tell your boys they're awesome for being so dedicated and hard working.