Good Grief! I never cease to be amazed by the outrageous things people do! Not only would I not make her another one, I would never lay my hands (unpaid) to fabric for her again...EVER! Obviously, she has no appreciation for your work. I guess that you could teach her a lesson - tell her to go buy all the materials for the next one and bring it to you. Tell her that your labor cost will be $_?__._?_, (way more than $20.00!) paid in advance! As soon as all that happens, tell her that you are "glad to do BUSINESS with her"
I'm sorry that this happened to you. It makes me sad and angry to know she did that to you.