Hi @Niall4 is it possible that YOU canceled the booking, not the guest? Normally once the guest cancels you'll receive an email like this:
We regret to inform you that your guest Meredith canceled reservation XXXX starting on 2016-11-30. Per your cancellation policy, your payout has been updated to $XXX. Your guest was refunded $XXX.
An adjustment of -$XXX has been applied to your account.
For more information on cancellation payouts, please see our FAQ.
Your calendar has also been updated to show that the previously booked dates are now available.
Regards,
The Airbnb Team
What you are describing is one of the penalties of a HOST having canceled on the guest - the penalty being a blocked calendar, preventing you from re-booking those dates.
You may have done so accidentally, at the request of the guest, but the result is the same. If this is the case, you must phone Airbnb right away and let them know that you're a new host, you didn't know how the process worked, and you canceled for the guest in error. It's super important to get this cleared up to show correctly.
Good luck to you.