Why is customer service important?

It will make the customers upset if there's no customer service because if they have problems or if the product they buy is not the one they want or refund, they can go to the customer service and talk it through. If the seller do not have good customer service the store can lose a customer and maybe more because of the word of the mouth. They are helping customers and do what they can for them, if there's no customer service then the store would have a bad reputation.