Tell her the truth since she appears not to be a true friend or even a good acquaintance. Be blunt. Let her know that a quilt needs to be what I call "groomed" before quilting. She did the work, let her finish the work. Give it back to her so she can do the grooming. And if the quilt comes back to you in an un-quiltable condition, refuse to quilt it. Even better, suggest to her that SHE can have HER quilt machined quilted and refer someone or a shop who can do it. Especially since it appears that she is making a profit off of your stash and your work.