[Help] Why my shipping is always "free"?

[hiquilling]

Hi all,

Here is my site: http://hiquilling.com/

Everything is fine, but the shipping is in trouble now. My service is free delivery for most of products, but not for all. Some of them need to have special pack and delivery, which is not free. Therefore, I set the "free delivery" and "sepecial delivery".
for example: this product is not free delivery: http://hiquilling.com/home/16-quilling-picture-3d-tulip.html

But it always appear to be free, right at the beginning, and even when customer choose "special delivery"

I do not know why? Can anyone help. Thank you very much.