Can't log in
As you can see on the screen, the trading site itself has disappeared. The person in charge is Hiroyuki Yamamura. I was only able to contact him through LINE, and he didn't even reply.
Others
The following is the original recommendation
ログインできない
画面の通り、取引サイト自体が消えた。担当者は山村浩之氏。LINE上だけでしか連絡が取れず、返事すらなくなった。