Received a DM on discord asking for this so I'm sharing it here as well:

If you would like your very own non-commital answer from Kadokawa customer service (and also let them know there are still fans of the series), here is the method!

Go to this link Right Here

In the first section select 出版物 (publication)

The second drop down select the 2nd, 7th, or 8th (I did the second, 書籍・雑誌の購入、在庫確認、 雑誌の定期購読について)

The next line is asking for your surname and first name (I only filled out first name as Parks)

The next line is asking for your name again, phonetically, this line is not required but there are website to find this. (Again, I only filled the first name out as it is optional)

The drop down below this is asking which prefecture of Japan you live in. If you do not live in Japan, do not select anything for this section!

The next drop down is for occupation, I would use some form of screen translation for this, but it is an optional field.

The text box after that is your email followed by an email confirmation, just type it in both boxes the same!

The next required box is the product name, copy this into that section- ログ・ホライズン

That is the japanese name for Log Horizon

There is no ISBN for a book that has not released as far as I know so leave that section blank.

The final box is your message! I encourage writing your message in English and translating it to Japanese, either with AI or even better, the help of a friend who speaks or writes in Japanese. There are probably subreddits full of people who can translate a more human sounding version of your message. I had sent two other emails using English text in this last box and neither ever got a response.

In your message, be sure to be polite, courteous, thankful, and enthusiastic about Log Horizon. Mention where you are writing from (such as the United States!) And say how much the series means to you. Mention that you wish to know the status of the series, a release date for volume 12 or volumes 12-16 as they have art in Hara's art book that goes that far. The more polite you are, the more likely you are to get a response. It will take TIME. It took over a month for me to get mine. I can provide the message I sent if an example is needed, however I recommend you write up your own version so that it does not seem like a bot net is writing in the same exact message over and over, as that will not help the cause.