@Komang-Pamela0
As the booker and canceller doesn't pay direct to you, it's for the best for you to refer them to contact airbnb help to get a full explanation and breakdown.
You don't have access to payment and refund information so you are in no position to clarify.
It's tempting to get involved, to be helpful, but here you aren't able to assist and as the booking is cancelled it's no longer a productive use of your time. My advice, politely disengage.