Bertha, a housewife, ordered a $50 dress from the Ace Department Store by telephone. She ordered it in light blue. The Store's delivery truck delivered the dress leaving the package containing the dress at the front door. Bertha found a light green dress in the parcel; she phoned them and informed them of the error and that she didn't want the green dress. The complaint manager said that the delivery man would return to pick up the green dress. Bertha waited but the delivery man never showed up. Bertha was billed for the dress. Does Bertha have an obligation to pay for the dress