SHANGHAI — It was looking like a banner year for business in China. The U.S. clothing company was expecting a 20 percent jump in online sales on Alibaba’s Tmall, thanks to the e-commerce giant’s massive reach. But executives soon learned that what Alibaba gives, it can also take away. The company refused to sign an exclusive contract with Alibaba, and instead participated in a big sale promotion with its archrival, JD.com Inc.