I feel your pain, but this might just be a painful lesson that will help you moving forward.
I have to agree with @Emiel1
If you do not have a property that can accommodate 30 dogs, why did you approve this booking? Even if you had to cancel, it probably would have been worth it.
I believe Airbnb should live up to its host guarantee, but I also believe that it is up to us as hosts to vet whether a guest is a good fit for our property based on the info we are given. And you mentioned you were given this info in advance.
We are a "pet-friendly" property but we charge an additional $20/pet/night recognizing that cleaning up after animals after *reasonable use* requires more (in this case, $600 would have covered the clean up). I think this is a good, but painful lesson for you as a host to develop some rules and policies that work for you and for your property and also to consider what you expect and require of your guests. @Debbie903