If a reservation in Guesty shows no payment collected, this does not necessarily mean the website booking engine failed to charge your guest.
Check the reservation source. First, look at the reservation’s source in Guesty.
If the source is manual, the reservation was created inside Guesty directly and never passed through the website checkout, so no card is collected at booking.
If the source is BE-API, the reservation came through the website booking engine. In that case, send the reservation code to support so it can be investigated as a website booking.