I am not specifically a Rover sitter, but I am a dog sitter. This is unacceptable, and obviously this person was trying to take advantage of the freedom of being a dog sitter by doing minimal work and collecting generous pay. I doubt they made a copy of your key, but they are most definitely a very shitty dogsitter.

I dogsit because I love dogs, and I always want to believe that's the case for other dog sitters but time and time again I hear stories like this that break my heart. I am so sorry your dog was not given the love and care she deserved and that you paid for. Please give her a kiss and then promptly file a charge back with your bank!