It's totally possible that the charge mentioned is correct. For one thing, AirBnB does not refund the guest's original booking fee. For another, your listing (like mine) uses AirBnB's "Strict" cancellation policy. Under that policy, cancelling at ANY time from the moment of booking up until 7 days before arrival incurs a 50% charge. Closer than 7 days, none of the charge is refunded. All that said, after the guest cancels, AirBnB gives you the option of refunding all or a portion of the money that AirBnB credits to you. The guest will still lose the original fee charged by AirBnB (the amount of which you can see in their booking).
Whatever you do, do NOT cancel from your end. AirBnB will ding you for that, and it will hurt your listing's visibility, etc.
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