they are testing your phone to see if you answer, if you answer, you "move on" to the next step, if you don't answer, they drop your number and DON'T pass you on to the next level.
Got a call from this number. When i picked up the phone , no response but the line was still in use.
I tried to call back but the recording said the number has been disconnected. Strange.....
I got 4 phone calls today. my friend tried to call back on her phone and it was disconnected......i answered 2 of the calls and both was just silence.....