Joann is a huge store, with fabric sales in the millions. If they shorted even a tiny percentage of their customers by an inch or two their annual sales would climb dramatically. This is only possible, because customers don't return unsatisfactory purchases. If enough fabric came back to the store and the company had to pay staff for listening to dissatified customers, writing refund tickets, and restocking merchandise when they could be racking up sales - things would change.
Use the gas to voice your discontent and let them know that online stores more convenient and have a much better customer service policy. A couple of times have gotten mixed orders from online stores and they sent the correct order and told me to keep the incorrect fabric.