called today, no message. Caller id "Seffner FL".

Don't be surprised if they call and you are on the DNC list, they are scammers, they break the law. They use "spoof" numbers which is why you get the "error" message if you try to call it back.... they don't want to be found out. And they use robo-dialers so if you don't answer before 4 rings it disconnects. If you pick up before 4 rings, you still might get disconnected because the scam "operators" are busy talking to other potential scamees.

If this is one of the scam "energy savings" companies, we need to know which one so complaints can be filed. The local electric utilities often have warnings about these scams. Some "save energy" scammers who have called me (yes I am on the DNC list): Florida Energy Conservation Advisors (they called AND visited my home with a hang tag on the front door), Advantage Energy, Bright Energy Advantage, Green Energy.

I have received numerous calls lately from several numbers, on both my cell and home phones, that hang up when I answer, and when I try to call back, I get a message that they are not working numbers. This number was a little bit different- a girl said she was calling about my electricity bill at my home address, and I asked if she was from FPL, at which time she hung up. Again, when I tried to call back, got a message it was not a working number. I am on the do not call lists as well.

I assume that you are referring to those free GEORGE W. BUSH PHONES.

Just received a call from 813-324-6621. No message left soooooooooooooo called number back. LOL recording = you have reached a number that has been disconnected or is no longer in service. Hum isn't that odd? Could it possibly be coming from one of those FREE OBAMA PHONES?

caller id "unavailable". typical rings 4 times then hangs up.

This is just one of the numbers that call constantly and leave no message.  I am on the do not call list.

Multiple calls even though we are on the state & national do not call registry which is stated on my message machine.

Calls and never leaves message answer the phone and no one's their

Called.  Answered but the line was dead.