It is the business practice of sending all clients' billing info to a separate company, who then does everything for you. It also allows a company to cut down on time and human resources spent on administrative tasks.
In telecommunications the automatic call-back is a computer telephone function which allows the user by the engaged addressee’s line or in the other case of the subscriber’s inaccessibility indicating the system to save the number of the called subscriber and make the call when the line will be available or when the called number is not engaged.