This thesis examines how customer complaints regarding mobile terminals are handled and managed during the after-sales phase. Mobile communication devices have become essentials of daily life in most parts of the world. The annual increase in the number of mobile handsets produced and sold brings challenges in maintaining standards of performance in accordance with customer expectations. Such expectations give rise to the issues of device quality and service quality. By reviewing existing literature, four published articles, and a proceedings paper, this thesis analyzes the best strategy for improving the handling of customer complaints regarding mobile terminals. The case studies in the articles employ different statistical methods for analyzing different variables and parameters that affect customer satisfaction, loyalty, and retention. The articles focus only on the customer-raised technical problems that are encountered in mobile terminals deployed in the field. The main customers in the current thesis are authorized service vendors that interact with terminal end-users. The statistical methods in the aforementioned articles are used to create a model that is useful for significantly optimizing problem resolution time. Results show that the perceived quality of problem resolution is closely associated with the perceived quality of problem description and perceived quality of the time spent in resolving problems. On the basis of the findings, several managerial implications are established. As a rule, training on new products should be provided to internal and external service staff to effectively manage the problems raised by customers in the field. Communication between mobile manufacturers and authorized vendors should be maintained on a regular and systematic manner to capture the business opportunities available to both parties. Such opportunities can be evaluated through panel analysis.