@Megc0 @Moka0
Do you live close to where they are staying?
If so pop over or msg them & have a word with them, and ask if everything is fine.
It gives you an opportunity to ask them to amend there numbers of people paying & payment owed.
Make sure you also put it in writing through the there Booking msgs to protect yourself from any issues that may arise.
Take your ph camera with you to gather evidence.
Ditto when they check put if you are the one doing the cleaning - it's always a tell tale sign of just how many people have stayed.
All the very best