Well, firstly you have to go to their official website, http://www.ancafe-web.com/RENEWancafe_web/top.html
Then from here you click on 'Contact' (Which is on the far right lower part of the page)
You then get a long bit of Japanese writing below, and you should scroll down and be able to see the word 'mail'
If you click on it, you can send them an email.
Hope I helped ^_^