I have discussed the importance of following-up on calls from customers - it's absolutely essential if you are to have any degree of customer satisfaction, let alone a profitable business. The same principle applies internally in a business. Some departments are notorious for not returning calls. When internal calls are received, they seem to be given a low priority, with the excuse given that the person was too busy.
Customer service has to be developed within an organization. Departments need to be made aware of the important role that they all play, and of the ramifications of not offering good service to other departments.
One of the best ways to get a feel for this is to spend time in other departments, seeing what happens when a customer's order isn't delivered correctly because of a simple typographical error or when a customer is lost due to a poor customer complaint resolution department.
The real issue here is to convince staff within an organization that every other department is a customer and they should be treated accordingly. One of the simplest ways to get this started is to implement a time limit for all calls to be answered. Make it realistic, but enforce it. All inter-department calls have to be answered within two hours, say. If a call isn't returned, there needs to be a good reason. While this may be seen as a tough form of action, it ensures that communication is speeded up. If a customer then calls you with an inquiry that you need to follow-up with another department, you will be able to do so confidently.