I had a very similair experience about 6 weeks ago when they had a shipping sale. Opened my box , thinking I had really over done it , and there was 20 yards of fabric I did not order along with my order. Fortunatley for them they also included the invoice for the 20 yards of fabric that belong to someone else. I called them immediately thanked them for my order, but told them of the extra order that got into my box.
They were so happy I called , since they would not have known where the "extra" order went because I had its invoice. They immediately put a gift certificate into my on line account. They sent UPS to pick up the "extra" and somewhere in Michigan there is a woman who loves cats( alot of cat fabric in the order) , whose order got to her.
It did not take me more than 12 hours to spend the gift certificate.