@Jake69 I'm sorry for your trouble. Airbnb support seems to be very hit or miss with how helpful they can be. The only way I've found them to be helpful is only when I have already figured out a resolution with the guest to which we both agree and Airbnb simply has to just facilatate the resolving the issue. I've found that if there is a disagreement, they will usually side with the guest.
As for the camera, you can look into buying one. You will have to double check with your city but I believe you can have a non-audio recording security camera in shared spaces such as living room.