Apple - I understand your situation but I think you should know that your intentions for posting your personal business here are not clear to us? First of all, your first posts were to tell of this story...now, I am not judging your Ebay experience; but, I am questioning your reasoning for divulging your story here?
Basically, we all know to be weary on Ebay, and we really can't offer you much advice as we do not know you. I think there may be a bit of a language barrier here as well; perhaps you have taken the buyer to be pushy and shady, where she is just blunt and direct. You may have been percieved as a liar when you have just not taken the precautions necessary to protect yourself when selling expensive items on Ebay.
The ladies here have given you great advice, attach a tag - offer no refund policy - get the bag authenticated by MyPoupette yourself - hopefully, you can move on from here and become a contributing member to the forum - then the ladies here can get to know you for you, and not for your Ebay experience.