Invalid contact details and guest no shows

Help - We have been established with booking.com for some years and recently we have had 3 fake bookings, where guests have given invalid contact details and these same guests have not come when they have booked the property.

This is obviously a problem because the property is being shown as 'closed' and so guests who actually want to book it, can't.

We have spoke to Booking.com but they have said there is not much that they can do.