Hi most mobiles allow you to block callers with no ID and they should not be dirverted to your voicemail box, they should go to a "lost in space" voicemail that will not bother you or any one else. For unwanted calls with a number, on a Samsung go to the callers list and tap the number it will bring up 4 icons, the last is a grey circle with an "i" in it tap on that and you will see a list of options at the bottom of the screen the 3rd one along is Block once you do this they can no longer call your phone and will get diverted to a non existent voicemail depending on the network you are with. With BT it just got lost in the ether but not sure with EE as the 1572 that works on BT doesn't work with EE. To be honest I am a bit sorry I moved over, but my landline and BB is still BT so I get that service there. Sorry cannot help you with other makes of phones but most have the Block options. To block Unknown caller ID's, from the calls list tap the 3 dots at the top right of the screen. click settings, tap Caller ID and spam protection and then chose the level of protection you want, again this is a Samsung. All the best
