Write a suspenseful story about a man who receives mysterious phone calls every night at midnight, but no one is on the other line when he answers

Write a suspenseful story about a man who receives mysterious phone calls every night at midnight, but no one is on the other line when he answers. As the calls continue, he begins to hear strange noises in his house and becomes convinced that someone or something is watching him. The man must uncover the truth behind the calls before it’s too late.