Left no message

Keeps calling but not leaving a message.  I thought I was on a do-not-call list.

Called again, answered this time and was told he was calling from "Protection Services".  I now know this is related to a house alarm installation scam I fell for accidently when I moved to a new house recently.  DO NOT GIVE ANY INFORMATION, TELL THEM YOU KNOW THIS IS A SCAM AND DEMAND TO BE REMOVED FROM THEIR LISTS.

also, when you call back it says disconnected or not in service.  total scam.  

would some agency PLEASE take on these scammers????

Have called me 4 times in the last month. I never answer. They have left a voicemail the last 2 times but I can't make out what they're saying.