How it works (brief version):- after checking conditions (checking if called party is not disabled) we look for voicemail checking callflow.- after that it checks that there are no notifications planned for this vmbox yet- if there are planned notifications, nothing is done- if not - the call is planned after given timeout- if call attempt was successful - there will be no further notifications- if call was not answered/was not successul and number of tries doesn't exceed limit, the next call is planned