Customer service management is the firm's face to the customer.  It provides the key point of contact for administering the Product Service Agreement (PSA).  Customer service provides the customer with real-time information on promised shipping dates and product availability through interfaces with the firm's functions such as manufacturing and logistics.  The customer service process may also include assisting the customer with product applications.

cf. Douglas M. Lambert and Terrance L. Pohlen, "Supply Chain Metrics," The International Journal of Logistics Management, Vol. 12, No. 1, (2001), pp. 1-19.