I'm so sorry you had a bad experience with PetSmart.

I know others have posted that they also have had negative experiences. It must depend on the store.
I've taken my pets there for years and never had any trouble. They always listen carefully to me and give me the cut I asked for. My babies have always been treated well whether I've stayed and waited or left and returned later.
I hope you're able to find someone you like to do the grooming for you or learn it yourself.