Once you have received a payout it no longer is under Air BNB control. Therefore, if you wish to provide a refund to the guest, you will be charged on a credit card. I had that happen once when a guest made changes after arriving, and since I am also a guest on this site, my credit card is on file with Air BNB.
@Mona50 If you are starting your business with a cancellation, even though you will refund, the automated system will post a cancellation notice under your reviews. This is not good for any host and often scares potential guests. I believe you will have a chance to add a response about the cancellation review. It would be a good idea for you to add a response and explain the cancellation.