I've had a daily call from this number for the past week, including one on Sunday afternoon. I answered three times, said "hello" and waited, but got no response each time. Take note caller: my phone has a call block feature and 813 444-5678 has now been added to the list!
I've received calls from this number for the last 3 mornings - no one there when I answered. When I called the number back a recorded message said I had received a call for telemarketing purposes and should press 1 to be put on "their" do not call list. My number has been registered on the government's do not call list for years but apparently, these people don't consider that to be a valid deterrent.