Companies can offer products and services as long as they satisfy their customers. Many factors affect customer satisfaction. One of the most significant factors is to resolve customer complaints quickly and accurately. Although there are many studies on customer complaint management and service models in the literature, there is no study found that accelerates the operation by improving the processes in the system with simulation support and provides the right solution by spending less resources. In this study, in order to fill this gap, the processes of handling customer complaints were analyzed to find solutions to customer complaints at the expected level and speed. In the study, firstly, the main processes of the complaint management system were determined, then the time distribution of each process was obtained by statistical analysis. Time distributions of the main processes were used to set up the simulation model. Then, the simulation model was run with different inputs and the new system providing the desired solution time was determined. The processes of the new system were determined by simulation. Finally, the process times and efficiencies of the new and previous systems were compared. Compared to the old system results, the average complaint closing time of the new proposed system was shortened by 38,9%. In addition, a new service quality model based on customer participation was proposed in the complaint system.