Paladiac the Pure
Major-General
Unfortunately though, this is part of the game, and is part of many similiar type games. If you are able to be on the game at regular times, the best method to protect your city (which you can also find reading the forums), is to time your collections so that they all collect at the same time each day. Things such as your Town Hall, Event Buildings, and many other buildings, are a hard 24-hour. Others, such as producing goods or supplies have varied times - on this, I would recommend using an 8 hour production, or if you are not relatively certain of being around each and every 8 hour occurence, do 24 hours, timed with your Town Hall. This will enable your collections to occur at the same time every day, and minimize the possibility of an outside neighbor of being able to plunder you.As I said, I like this game but I do find that being able to steal from another player is the worst thing and (in my opinion) should be discontinued.
On the plus side though, you can also plunder your neighbors (your choice, 100% if you want to do this or not - however there are the odd quests that will require you to plunder, but those do not happen often).
Your neighbor plundering you is just a minor irritant - like a mosquito, Take it for what it is, accept and move along, or do not accept and move elsewhere. The irritation of being plundered is just that, irritation, but it will not really affect your game play. As far as your Goods production (if that is what is being plundered), ensure you are only producing those goods that you are receiving the 5x bonus on - and have a few of them - so even if one gets plundered, you still have a couple others suppling you with goods to use in the game.