Go to the Booking.com booking for which you need to mark the card as invalid. You will see a Booking.com tab:
Mark credit card details as invalid
Click the button "Mark credit card as invalid" if the details provided to you by Booking.com are not allowing you to take a payment.
Once you click the button it will send a request to Booking.com and they will request new card details from the guest and re-send them to you.
You have three attempts to obtain valid card details.
Report a No-Show guest
If a guest doesn't turn up to your property when they are supposed to, you can mark them as a No-Show to Booking.com.
Once you click the button Report No-Show it will trigger a notification to Booking.com so that they are aware of this