I would have turned the tables on her with her own words. I would have made a big deal about how little her sister charged I would have talked and praised the sister for all she was worth how she was able to do that and still make a profit. I would have said I'm certainly getting in touch with her and tell her you told me about her doing a queen size quilt for $50. I want to learn how she manages to do that. And I'll tell my customers that have a lot of quilts that need to be quilted she will do queen size for them for $50. The woman will probably stammer and backtrack about her sister. LOL When someone is rude or snotty I make a game of it and never let emotion take over.