This people keep calling, a click is heard, some spanish speaking in the background is also heard and then they hang up!
It almost seems as if they just want to keep you on the phone for a certain amount of time only!

They called, I picked up the phone, no answer and then I hung up.

they call and hang up when you answer. you call the number and a recording comes on that the number is disconnected.

This comes up as "F.A.S.T. on the ID - when I answer, all I get is a click, then silence. I do know that it's a land line out of Miami. I called the number back, and got a recording saying "this number has been temporarily disconnected". Almost sounds like it could be a fax line, but without the usual accompanying beeps.

Received a hang up call