They never leave a message if they do you hear 100's of voices, and For the first time 01/06/17 someone left a message did sound like broken English. They said its a debt collector enterprise. Pff i have nothing in collections.
It's your legal right to have these calls stop. Sue them under the FDCPA and TCPA if they violate the law (e.g. using an auto-dialer to call your cell phone)