@Michelle0
I agree with @Kath9 I think its to late. I would let it go so you don't get the bad review. I would also not review them so they don't receive the email that says Michelle just left a review leave a review and see what she said.
This is what I did to discourage these situations.
In my Booking message I added:
Reservations booked must be booked by the person staying.
Also, please provide your reason for visiting e.g., visiting family, heading to Yosemite, etc.
In my Additional rules I added:
This accommodation is for a maximum of two. Hosting additional guests on the property is not permitted at any time and will result in additional charges.
A profile photo is required at booking. The image must show your face—a photo of a sunset, sports team, or a dog, for instance—is not permitted. All bookings must be booked by the person staying.
And in Fees under Extra guest fee I added
After 2 guests, $25 per person, per night
If you get documentation of the additional guests and I am told that Airbnb will change the guest the additional fees if you have it in your listing.