When messages are taken within your company, your callers should not be told to expect your return call with casual reference to “shortly,” “as soon as possible,” or “call you right back.” As the chart at bottom of IBM illustrates, there is a wide range of interpretation placed on vague phrases.
Most calls have some degree of urgency and problems arise when you fail to reach the caller when they expected. Work scheduling may be disrupted. Deadlines could be missed. Commitments are broken or business is lost. Coordinate language with your phone-answerer and give your callers a specific time frame in which you will return the call.