I'd raise it with her. And maybe get some other quotes as well, so you know how hard you'll fight it.

Do you have a contract/agreement?

how is the service different for an employee vs the owner? It is not like a hair place where you have more junior stylists and the master or a law firm where your have associates billing one rate vs partners a whole different tier.

Our dog walker service uses different prices for different walkers. The owners of the business charge $18/walk whereas their more recent employees cost $16/walk. We decided to use an employee at $16/walk for the better part of a year and she quit with no notice. The owner took over her walks and billed us for $18/walk. I am kind of annoyed at this because we had all agreed on a service and price. It's not really my fault her walker quit on her and I'm annoyed at getting charged the extra money for the same service just because her employee quit.

Am I being unreasonable?