Whilst it is fairly obvious there is an element of leaders using it for controlling the people, it doesn't mean that the basis is invalid.
But by the nature of spiritual matters there is no obvious proof: although if you took the time to experience, with an open mind, the evidence given by good mediums you may find there are things for which the most simple answer is that there is more to existence than this material world; and start to be less dismissive of groups who try to explain their beliefs regarding it.
But ultimately your question isn't a reasonable one. It boils down to, "I think this impossible to prove thing is untrue, can anyone prove this impossible to prove thing is true to me ?"
Or I suggest you wait until you depart this mortal coil and discover what actually is, for yourself.