how can i stop all these silent calls i get on my landline phone

i keep getting calls on there and they wont talk and keep calling , i block their number and they still call, im getting to the point where i cant even go to the bathrm and they call, i reported it to the donotcall list im on but they still call, any suggestions? i take off the phone when im sleeping, i answer it thinking it could be something important, will not answering it help me get less calls? do i need to report it to the police?