The purpose that the author wants us to know is simple. The lesson is you can't trust everything you hear. This becomes clear in this novel because these phone calls were fake, but people believed that they were real and that they could actually talk to the deceased. Mitch Albom explains to us that you may listen to those you think you can trust and rely on, but sometimes it is to good to be real. It would make losi g people a lot easier if we could talk to them after they die, but you can't. So, Mitch Albom just shows us what we thought was going to happens does.