https://www.intsys.co.jp/contact/
Yup.
I, too, have the 25th-26th down to contact Intsys with my expression of disappointment about this news (if it ends up going from rumor to confirmed but it is looking likely...), as well. And I encourage anyone who feels the same to try to contact them as well. Maybe they'll consider their moves for future games if enough are sent their way. BUT OF COURSE, NO DEATH THREATS OR INSULTS, PLEASE.
Though that's the only contact I know. And I doubt they have a twitter... (if they do, please @ or dm me it, please?)