I agree with what others have said which is to give her time to respond, but I would not give her more than 3 days! She knew at the time that she was charging waaaaay more than she should for shipping. Send her another email and tell her you will wait 3 days to hear from her and then you will file a complaint with Ebay, plus leave negative feedback. Save your package just in case you need proof.
That's ridiculous, and gives Ebay and other sellers a bad rep.