Fighting annoying players

I had a topic in general discussion, however it may be better suited here.

A level 13 player moves his main into the middle of my alliances territory and begins stealing our forts and oasis's. His army isn't massive, just 4-6k cavs. So making him cry and running home shouldn't be a problem for the #1 alliance right? Unfortunatly I've come across a situation where conventional tactics do not work. 

Pin him? He has no intention of running away and according to him he has $14 million in the bank so money is not an issue for him.
Capture his subs? Almost done. Just 1 more to go.
Farm him? I do and get a nice take too, but again he has the money to replenish.
Steal his oasis's? I've spent quite a bit of time looking all over the map for them and I can't find a single one with his name on it. I'm guessing he just buys the resources he needs.
Go after his alliance? We are at war, so that changes nothing.
Just destroy his army? Easier said then done. He has withdrew from battle 8 times from me alone. Guessing he has quite a few coins as he is able to boost his last sub like there is no tomorrow.

So I'm out of ideas. I'm not sure if the devs and admins have considered the situation, however short of moving the alliance (which would be easy for him to follow) what could be done to stop a player who uses annoyance as a weapon?

Just don't respond to anything he says or does. Keep troops out hunting and resources in market... Eventually he'll get bored with you, as he's only doing it because of the reaction he's currently getting from you. Just act like he doesn't exist.

I agree with Kitten.

He's like a resource farm right there in the middle of your territory, right?
So it's like a convenience store.

No reason to get too worked up, although I guess I would be a little if that happened.