@Reinhard-With-Sheila0
Of course it was right of you not to accept the guests.
Even better and in order to cover yourself in future (or even now still with this booking) is to immediately call Airbnb to inform them.
It seems that guests have discovered lying in order to get refunds, so if the host
1) doesn't inform the person who booked on the message page about something (like here finding out it's a 3rd party booking),
2) and also doesn't immediately call Airbnb about the problem,
there is good chance they will and complain of not being able to contact you, or any other complaint they can think of to get their money back (loads of such examples in this forum!)
There's also a good thread about how to best add a 'forgotten' guest on arrival before they are let into their accommodation. This is very helpful and can be applied in various situation:
https://community.withairbnb.com/t5/Help/Do-I-pay-the-100-penalty-if-a-booking-is-made-for-one-perso...
https://community.withairbnb.com/t5/forums/v3_1/forumtopicpage/board-id/listing-and-reservations/pag...
contact Airbnb
Hope this helps.