Hello @James744
I am so sorry to hear about these awful guests. Did your CCTV pick up signs of additional guests coming into the property or was it just the guests who were staying who partied. It must be awful to find your property in this state.
If you couldn't get through by phone, why didn't you notify Airbnb online or via their social media, so you could lodge was claimed before your next guest checked in? This would have prevented this issue with you not being able to submit a claim from occurring.
As you know with any insurance claim you have to meet their T&Cs in order to be able to submit a claim and sadly in this case you did not.
During Covid especially it's always a good idea to leave a day in-between guests to ensure you have time to do the special cleaning needed and as a buffer in case of any issues with guests.
In your situation as you aren't able to make a claim via Airbnb you could make a claim on your home insurance for STRs.
Best of luck.