@Michael1207,
regardless of the details in the strata laws and whatever applies to your building, your Airbnb activities have obviously unsettled your neighbours. It may work out better if you were to communicate directly with the body corporate and find out exactly which particular issues, activities or occurances have triggered the letter. If you can address their concerns and manage things in a way which does not disturb the peace of mind and amenity of your neighbours, you may be able to continue to host airbnb guests.
This push-back issue is not a lot different than having a stand alone home in a street. If your Airbnb activities do nothing to benefit your neighbours, and instead cause them disturbance or concern, you will experience a negative reaction. no matter what the actual law states as your rights.
If you can't work things out harmoniously with your neighbours, you will both experience a drop in your quality of life.
If you don't have positive and trusting relationships with your neighbours, they are less likely to support your activities.
Consider this: What are you doing to build good relationships with your neighbours? and what is the benefit to them from Airbnb?
best regards, Christine.