After the accessories are sold, it is not the end of sales, but the beginning of occupying the market. After sales services include packaging services, delivery services, installation services, three guarantee services (repair, replacement, return), troubleshooting, providing technical support, sending product improvement or upgrade information, maintaining regular contact with customers, product use contacts, establishing customer files, collecting and sorting customer information, etc. Enterprise marketing without after-sales service is sales without credit in the eyes of customers. Products without after-sales service are products without guarantee in the eyes of customers.