Customer service is the act of taking care of the customer's needs by providing and delivering professional, helpful, high quality service and assistance before, during, and after the customer's requirements are met. The important of this work is the service, communication and building a good relationship with every part in the organization. The key to good customer service is building good relationships with customers. A happy customer will return often and is likely to spend more. Point of view on growing business, Customer Service is very important. Because it is often the only contact a customer has with a company. Customers are vital to an organization. Some customers create a lot of revenue to the company. Consequently, when they have a question or product issue, they expect a company's customer service department to resolve their issues. The service is a measure of the quality of the organization. And also trust helps customers to continue using the service. The most important duty of DKK company's Customer Service is a technician. Because the main products of DKK company is a testing equipment machine in the Industrial factory such as Environmental test chamber, Industrial oven, Vibration test system, Occupant safely test system. The basic property of technician that must have a good knowledge of basic mechanics. With more experiences will be get a good consider. Not limited to qualified education because everyone must get the training until the really expertise. Customer Service must have patience, responsibility, punctuality, good relationship with customer service mind. Customer Service is important to increase the income for the DKK company. Because some goods, the customer must use a really skillful from the DKK company to install or repair and modify, so the service must have expertise about the goods for build trust customer relationship in DKK company. The difficulties in the work of the DKK company is the DKK company's employees are Thai people but machines mainly imported from abroad and also have the manual is in foreign languages, that means the technician must have very understanding, expertise and accuracy. The important expense in DKK company is general expenses, such as fuel cost of delivery trucks, the salary of the employee and the cost of spare parts of the product. Customer Feedback on this work quite well. No problem, because the DKK company delivered on time, take care customer every step until customer get goods.