Can't cancel a new booking?

I realised I’m double booked for next year so immediately tried to cancel via Airbnb. One week later, the booking is still there…
Emailed Airbnb and they’ve not responded yet and it’s about 4 days now.

Why not give them a call.

If you cancel as a host they will impose penalties (see Airbnb Help Centre - host cancellations)

Yes I’m aware of the penalties. Nothing I can do I’m afraid.