We want to cancel reservation of our guest

Hello!

Yesterday a guest made a reservation for 2 nights in our B&B in France.

Afterwards she send an email that she will also bring her 9 month old baby.

Our house is "old" and is very noisy. That's the reason that in our reservation policy we say that kids are not allowed. I send her an email with the request for annulation, but she doesn't answer. 

Now I send a request for cancelation via Booking itself. But the customer doesn't respond on this request. 

Can someone tell me what to do? Can Booking finalize the cancellation for me?

For our other guests it's not an option to welcome this family with baby.

Hope you can give me advice!

Kind regards, Audrey