@Mayumi10
A cancellation more than 60 days in advance you should be eligible for a full refund on the super strict policy. Does it say super strict on your booking confirmation ?
https://www.airbnb.com/home/updated_cancellation_policies#super-strict-60
Does it say super strict on your booking confirmation ? If so, you should be able to get a full refund. The cancellation policy at the time of booking is the valid one and a host cannot change this.
My best advise would be to contact airbnb with the issue as in my book things does not add up.
Please let us know how it goes as this is a real mystery.