How do you book this hotel? Is it by calling them directly?
We called them and then they provided a reservation confirmation via email. We also arranged transport to and from Surabaya with them.
When I went in Jan we just turned up asked to see some of the different rooms available and booked on the spot. There were plenty of rooms. It may be possible to book online although you won't get to see what the room is like before you pay.
Get an answer from Lava View Lodge staff and past guests.