My mobile was rung from this number. No-one on the line. I rang the number back and got bogus pre-recorded voice claiming to be "Cisco answering system". that said 'operator was busy & to call again later'.
May be carriers are fattening up their bills? Like TPG has been doing ever since they switched us to Vodafone network. Calls divert to " call catcher" that was switched off: and magically keeps re-activates itself at 15cent each multiply time