Return it and the $100 to her and tell her that she needs to find a more experienced quilter that could possible quilt it in the condition it's in. Then fold on this losing hand and sever your "acquaintence" asap. I, too, used to have a user in my life. It took me a few months to see what a mooch she was, a month of trying to get her to realize it and stop, then a month or so to rid myself of her. Some people just go too far.
Let me edit this. Return the top to her. Ask her how much of the hundred she wants you to keep in return to replace the fabric in your stash. She probably won't want you to keep any of it but that will be a good start on letting her know that you won't be walked on anymore.