Caller never leaves any message. In most cases it is a robot call. System goes through a list of telephones and if no answer system moves on. You may get upset but machine has no feelings. If after many calls if someone bites on the offer that is good enough. Congress has to make a strong law, but congress will cave in to lobby. Moreover, Congress cannot control other nations to act. It is not difficult to see that someone is making money, otherwise, it would have been closed out long back. Carriers cover their cost by utilization of capacity. We are just suckered or victim.