Miss Caroline may have good intentions but in her inexperience and insensitivity, she doesn’t listen to what Scout has to say. It doesn’t help that Scout has a bit of trouble communicating to the much older Miss Caroline.
Scout has an intimate knowledge of the social structure and mentality of Maycomb. Miss Caroline is an outsider. When Scout tries to tell Miss Caroline that Walter won’t take the quarter because he is a Cunningham, Miss Caroline has no idea what this means and thinks that Scout is just trying to challenge her. Walter won’t take the quarter because he comes from a poor but hard working family. He just doesn’t want to take a handout. This is also why Walter doesn’t like Miss Caroline at the start.
Miss Caroline also scolds Scout for reading with Atticus, which is just contrary to whole spirit of education. The fact that Miss Caroline is an outsider adds to her problems communicating with the class. She tries but is impatient and this results in a basic lack of communication between her and the children. Miss Caroline did not take into consideration that she might benefit from the advice of the children.