You can take up a course in customer service online. Courses like these are readily available online, and you can take them up at your own pace. Some tips that you can learn from such courses include things like how to handle irate customers and effective ways to interact with them. In addition, you can also learn tips on how to create a good impression on the customers, and how to resolve customer complaints. Online courses on customer service can be taken at the click of a button. There are many online courses on customer service like mindcypress's customer service management courses.
https://elearning.mindcypress.com/s/store/courses/description/customer-service-management