As others have mentioned, you won't be able to file a dispute over the excessive shipping charges, but she definitely didn't pay $33.00 for shipping, so you could leave feedback reflecting that.
I ship to Canada a lot from the US, and the customs forms that you have to use for Priority or Express are different than if you ship first class. The little green form (that she used) is for first class; a large white form is used for the other more expensive services. You might try sending her another e-mail to mention this, but from her first response, it doesn't sound like she'll refund.
What she marked the customs form for won't make a difference either though; customs can charge duties for any items that are valued at $50.00 or more; I don't know if that $20 difference on your package would really change what you got charged, though you can definitely call customs to see.
I ship to Canada a lot from the US, and the customs forms that you have to use for Priority or Express are different than if you ship first class. The little green form (that she used) is for first class; a large white form is used for the other more expensive services. You might try sending her another e-mail to mention this, but from her first response, it doesn't sound like she'll refund.
What she marked the customs form for won't make a difference either though; customs can charge duties for any items that are valued at $50.00 or more; I don't know if that $20 difference on your package would really change what you got charged, though you can definitely call customs to see.