I think many phone companies have an incentive to keep the voicemail systems up and running - if your call is forwarded to a voice mail service the call is conn

I think many phone companies have an incentive to keep the voicemail systems up and running - if your call is forwarded to a voice mail service the call is connected and therefore billed. If you reach the automated messages for failed call setups (busy/terminal cannot be reached etc), they are not billable.