Called and hung up

I get a couple calls a day now from this number.  If I don't answer, they don't leave a message.  If I do answer, they hang up.

I too have been getting calls from this stupid whomever, it is... here's what I know: this is land line from South Central Bell in Charlotte, NC; the phone has an owner who is registred.  You can get more info if you're willing to pay for it.

they keep hanging up when answered and dont leave messages!  Annoying as hell!

I have received phone calls from 704-549-4393 on three occassions.  I'd answered the call and they would hang up.  The third called I answered and a woman asked if was such and such.  I was curious since she knew my name.  After I confirmed who I was, she hung up.  When I call back that number I get a busy tone.  I called my phone service They said the call comes from Bell South Applied Technology.  I blocked the number, but that doesn't explain why that lady is making harrassing phone calls.