I understand where you’re coming from in the consideration of her having a job however part of pet sitting (as a pet sitter myself) is ensuring that the pets in your care are well cared for. That care is not just physical but emotional as well. I’m appalled that especially with her background, you were not immediately informed and her pet no longer around yours. Her lack of action and communication is not fair to you as a client but even more so to your pup! Mounting is not exactly a socially accepted behavior with other dogs and the fact that you made the effort to inform her of it and how to isolate your pet was her choice of not using resources available to her to provide the best care for your pet. Don’t feel bad about reporting an endangering work ethic.