I can understand you getting the cleaning service in as soon as possible. While insomnia's suggestion is great, it would take time and you have to live there with your kids and not be disgusted every second. So the clean-up is done. The money for the clean-up should in theory be deducted from whatever you owe.

But KEY THING in your note above. You say you employed "our babysitter." That is someone you have already had over to look after your kids. This is an ongoing relationship, not a one-off dogsitting event. That makes this more serious.

Your trust has been violated. Trust is everything. Do you want to continue the babysitting relationship? If you do, then you have to rebuild trust.

So here's my suggestion: Have her over (ostensibly to pay her) and ask her to tell you how it went. See how she handles the question. It sounds like you're willing to give her the benefit of the doubt. Will she tell you what happened? If she doesn't tell you, then tell her what your found and what it cost you. In either case, ask her how she might make this up to you. See what she says. Then decide.

There might be a lot at stake for her - babysitting jobs, her reputation in the community, and so on. Get more information.