Address (can be used to send offline claims):
MTGOX Co., Ltd. Office of Bankruptcy Trustee
Suite 202, Kojimachi 3-chome Building
3-4-1 Kojimachi, Chiyoda-ku, Tokyo, Japan
(open from 10am to 5pm on weekdays) (Japan time)
Please note that Kraken Support does not have a phone number to call for support. Any phone number you find claiming to belong to Kraken is fake.