After changing the device, books disappeared.
Install the app on your new device and sign in with the same account you had before the change.
You can sign in even if you have already cancelled or changed your email address.
After signing in with your old account, please go to “My Account” and change your email address, if necessary.
However, if you have forgotten your password, you will not be able to sign in.
In that case,please contact our customer support with the following information:
1)Please let us know your purchased book data – book title, volume, and category (manga, light novel, etc.), as well as purchased date and time.
Ex.”Konosuba: God’s Blessing on This Wonderful World!, Vol. 5″（Light Novel）- purchased on 2018/04/24 6:00 pm
2) Payment option chosen
3) e-mail addresses possibly associated to BOOK☆WALKER