Customers would always be right in their own mind and the only thing we can do, as employers or entrepreneurs is that we can learn how to handle such challenging situations just like in your case. She could have admit and apologized when she eventually confirmed the size of the frame and also, about the color of the frame, she could have been patient or even asked politely to hear from you.
Customers can never always be right all the time, they are wrong too.
People like them should be dealt with carefully so as not to miss them and even if it worth losing them, you wouldn't mind because there are people like that. Lol
You are welcome 🙂