What can we do to dog sitter who wouldn't accept her responsibility for my dog injury and disappear from Rover?

I understand that Rover has "Rover Guarrantee". This post is less about money, but more about how to not let people easily get away from what they should be responsible for.

Our dog got bitten badly by another dog while boarding with this sitter, who we boarded with for a few times. But this last stay didn't turn out well. Our little mini dachshund got a wound on his head about two inches long, and deep all the way to the bone! Long story short, she left the two dogs who are not very much familiar with each other alone in a room with just a kid, and she was not there when it happened (this is what she said to me when we picked up my dog). She didn't tell us anything until when we pick up our dog - one day after it happened, and left our dog sit there with fear and pain without bringing him to a vet.

After taking care of our dog in the vet, we asked her to reimburse the medical bill. The sitter refused to take any responsibility, blocked our numbers, and by now closed her Rover account.

Just in case she comes back to Rover again, try avoid someone who call herself Cynthia with a dog called Biscuit leaving on Campus Way near Woodmore Town Center, Maryland.

Any comments or suggestion on what we can do, besides submit claim to Rover Guarantee, would be very much appreciated. We are ready to take further legal actions and don't want people like this walk away without any consequence. Thank you.