I have regularly been getting calls from number who call and if I don't answer they don't leave a VM and if I do answer, there is a pause for 10-20 seconds and then they just hang up. This number called me today and yesterday, no voice when I answered both times. This week I also got one from (02) 8766 1878 where the same thing happened. I've also gotten called from (02) 7245 4918, (02) 8319 4722, (02) 8271 6792, (02) 8271 6721, (02) 8271 4746, and (02) 7259 1807 - all since the end of Feb. I get an average of one call a day on weekdays. The numbers often seem to go in pairs eg (02) 8766 1474 and (02) 8766 1878 where number start the same but end differently. I'm no longer saying anything but "Hello" as I'm concerned that its scammers trying to record my voice to use with voice recognition software.