I don't really think I know the whole story here, but things DO get lost in the post. Did you ask for insured shipping? Did she offer any? I know that I say that people can have their work shipped regularly or by registered post (the latter costing more) but if someone takes the first option and it goes missing, there is nothing I can do about it, and it's honestly not my fault.

Could it be possible that she really did send it to you?