This is not a nice thing to suggest but find out about the local newspaper, or other forms and communication and see about putting an ad in the paper asking if anyone else has had this problem. It would be interesting to see how often they cheat others and refuse to make it right.
I do not put up with a stores arrogance and would never return there again.
The LQS I go to I love. They are so helpful but I do watch them cut my fabric. Wish all stores who sell fabrics cut the way they do. I also take classes there.