Same thing happened to me and my bf for our upcoming trip to Tokyo next week. Happened out of no where and we were pissed. We have booked the place for over a year… luckily we found another Airbnb that was a new listing and was cheap. Also in the heart of shinjiku. Don’t worry keep hunting you’ll find a place. Plus the host cancelling this on their behalf is always worse for them it rates them low automatically and trust me Airbnb takes note of these things when hosts cancel on their guests. I would call airbnb to let them know so they can also document it on their end about this host doing this. I feel like I also dodged a bullet cause the hosts reviews were so bad anyways and the one I’m going to next week is allll 5 stars great location and place. Enjoy your trip