Possible Clues:

• Hard to contact us? Ring in
• Rings American being cruel
• Label old American 'heartless'
• Visits from stand-by engineers, say, when temperature goes cold
• Hard time avoiding requests for assistance?
• Heartless love, something superficial and hard about it
• Contact the Guardian about job centre that's unfeeling
• Unsympathetic
• Cruel, insensitive
• Not feeling hard skin that contains oxygen