My dog sustained multiple dog bites at the meet and Greet. My Boxer was attacked by her dog. We have a vet appointment this evening.
This woman should not be watching dogs. The next dog, that might be smaller, could be mauled to death.
Again, this woman should not be dog sitting other dogs. How is this reported?
Wow, that's horrible that a prospective sitter had an uncontrollable dog herself. Not good at all. I share your concerns.
As for Rover, you can call their regular Customer Service number to report: [Edit: Rover’s contact options have changed. Visit the Rover Help Center at https://support.rover.com/ to find the phone number, help articles, or chat with the team] or if you don't feel like you are getting anywhere with them, there is a Trust & Safety group and its number is 888-727-1140.
Finally, You also need to report the situation to your local police. Some people don't want to take that step but, unless it is documented, then that dog can continue to be a threat to other dogs. I don't know where you live but it does need to be reported.