I think you have grounds for a change (Article 12 mitigates ANA's responsibilities in the event of a force majeure) - seems like it would be worth trying to call ANA again.
From ANA's Conditions of Carriage, Article 7 (Rerouting, Failure to Carry and Missed Connections):
(B) Involuntary Rerouting
(1) Unless otherwise provided in sub-paragraph (2) of paragraph (B) of Article 12, in the event that ANA cancels a flight, fails to operate a flight reasonably according to the schedule, fails to stop at a Passenger's Destination or Stopover point, is unable to provide a Passenger with his/her reserved seat or causes a Passenger to miss his/her connecting flight on which he/she holds a reservation, ANA will, at Passenger’s option, follow either (a) or (b) bellow
(a) ANA will have the option of providing any of the following remedies:
(i) carry the Passenger on any other flight of ANA on which a seat is available;
(ii) either Endorse to any other Carrier the unused portion of the Ticket to request such Carrier to carry the Passenger or request other transportation service to carry the Passenger; or
(iii) effect a Rerouting and carry the Passenger, by any other flight of ANA or any other Carrier or by any other transportation services, to his/her Destination or Stopover point indicated in the Ticket or any applicable portion thereof.
(b) ANA will provide an involuntary refund in accordance with paragraph (C) of Article 13.