Hi @Jill193
It sounds like you are listing with multiple letting companies and haven't sync'd your calendar for a 'double booking to happen'. You need to go through quite a laborous process to remove Instant Book. If you are sure you have done this, then Airbnb can see this and will lift the penalty if it's a technical glitch.
You are being penalised becauase Airbnb takes host cancellations seriously because of the impact you have on guests by cancelling their bookings. Personally I am glad this is in place.
You can of course contact Airbnb and see if they will be flexible in the circumstances you have outlined, if it turns out that you in fact hadn't turned IB off.
If you don't want to do that. Have a look at their Help Centre and search for deactivating or cancelling your list and it tells you the steps you need to take.