Hello @Jayne75
Sorry to hear about your guests @Jayne75
I agree with @Branka-and-Silvia0 say you are sorry that they have decided not to stay but that your place is as described in your listing. And that if amenities like having a queen bed was important for them, then they should have looked for a listing that provided this.
Regardless of whether you refund them or not, they can still provide you with a bad review. Remember you will have an opportunity to review these guests too, so can be honest about your experience.
Airbnb will refund the guest in line with your cancellation policy, if they are not entitled to a refund, you can say to the guest if once they cancel you get a replacement booking you will consider an additional refund.