@Jacquie40
Sorry to hear about this, very distressing crime to be a victim of. Truly dreadful.
With a disclaimer, my comments are purely layman's, not based on legal expertise, which you might seek.
First, report to the police and obtain a record of what happened.
Airbnb do not cover this situation via insurance, and if the guest reports, maybe just a goodwill response.
Even if you have home insurance, it's supremely unlikely to cover third party personal goods and even so, if the guests had left open the door, a claim would be rejected because of lack of due care.
There are some 'innkeeper' laws around the globe, thus normally hotels aren't liable for third party guest possessions unless they are kept in the hotel safe, so you can see these ' not liable' signage frequently in the trade.
If the guests have travel insurance, they should pursue a claim based on the policy coverage.
It sounds like an opportunistic theft, but you can undertake a review of burglary prevention strategies.