Hello @Christine508,
Unfortunately, you will probably not have much luck. Airbnb is pretty forgiving about their penalties for cancelling under "extenuating circumstances" (floods, fire, major illness/hospitalization), but most likely you won't get anywhere just because you were unfamiliar with the settings.
Definitely try, though. Call the phone number, 855-424-7262. I have used it twice and have always found a human within a few minutes.
Did you have instant book on? How did the person book without your OK?