Researches on after-sales quality have centered on home electric appliances, figuring out how factors influencing after-sales service quality are causally related to customer's behavioral intentions, via consumer satisfaction as an intermediary parameter In most cases of after-sales service in home electric appliances, upon customer's request, service agents make a visit to where the appliance is installed, and check the product and do repairs. However, in case of a small portable device such as a cell phone, which people carry around at all times, most of the times customers themselves show up at the after-sales center, and demand a check-up and repairs. The main difference here is that the after-sales services are provided when a product can no longer perform its basic function and customer dissatisfaction is already up. In this case, the basic function of a product corresponds to must-be factor according to Kano model. The goal of our research is to identify critical factors for effective and efficient after-sales service, and how to monitor them on a routine basis. In our research, the quality after-sales service consists of three dimensions, interactive quality, result quality, and physical environment quality. We set up variables for each dimension, which would measure from customer's perspective key determining factors in service delivery process. Instead of focusing on customer satisfaction aspect, we focused on how after-sales service factors contribute to addressing customer complaints. Additionally, our future research would aim to verify how customer's behavioral intentions are affected, as the resolution of consumer complaints becomes more successful when adjustment of relevant quality factors improves after-sales service quality.