@Andre110 , looks like you are fairly new to hosting and you have one nice review already. Still, I think you are not familiar with the basics of Airbnb, how payments work, etc. Please study that and educate yourself on that, it will help you with questions and possible problems! For sure study up on what cancellations mean to a host.
As a host, you do not handle the financial aspect of a booking - Airbnb does! You only get the confirmed booking notice from them when payment from the guest is secured. If not, you don't have a booking, simple as that. You certainly never ever collect money directly from the guest!
I looked at your listing, and your calendar is wide open, except for June 17/18/19. So I hope that "reservation" you are talking about is not someone already staying at your place right now - or if it is , then apparently payment was/is guaranteed by Airbnb, or you blocked out those dates yourself. Only you know...
But if that guest you are talking about has a date in the future in mind, as your calendar is wide open, that means you simply don't have a reservation - refer her back to Airbnb to get her financials in order so she can make a successful booking, not your problem, hers.
Btw., looking at your listing, a charge of $100 per night for max 8 people seems incredibly "cheap" to me. Is that really what you want? for sure, go back into your listing and fix that typo at the beginning, where you use the word "fix", but obviously you mean "fit". It just makes a much better impression if you correct that. Good luck with everything!
