Last Empire War Z

What now happens ? If you're still getting a message to contact iTunes Support that is what you still need to do.

Have you contacted iTunes Support as instructed by the message ? If not you should do so, we can't help : http://www.apple.com/support/itunes/ww

If you want help you have to provide details. What does 'not work' mean ? What happens when you try to buy something ? If you are getting an message what does it say ?