The competition among the firms become fierce and fierce in the Korean ISP industry. In this stuation, customer loyalty is the main driver of the company profitability for growth. Major players in the Korean ISP market try to increase their customer loyalty by investing in the improvement of service quality and responses on customer complaints. In this study, we examine empirically the importance of the responses on customer complaints between customer satisfaction and loyalty. Our analysis result implies that it is necessary for companies to reconsider the role of the responses on customer complaints among the satisfaction, the loyalty and future profitabilty.