I receive a lot of Robo calls and in an effort to stop them I’ve set my ring time to 7 rings. Hopefully Robos will hang up before then. I’ve noticed that when a call comes in that has no Caller ID, after 3 rings it stops and disconnects. When I check my call logs it shows as answered and a charge shows. I don’t understand why this happens but only for no Caller ID numbers. A normal call goes to voice mail after 7 rings if I don’t answer. I’m hoping someone might have an idea about this. This kind of call shows answered after 3 rings, goes to voice mail and of course leaves no message. Any help would be appreciated.