Received it too... Caller kept quite for awhile when I answered. And then mumbled something, before hanging up.

Same happened to me on 11 Feb, 2014.  Silence for a while, followed by a sigh before "she" hanged up.

Received call on 13 January 2014 but when I said Hello several times, the caller did not respond & then the call was cut-off.  Today, I received a call from the same number & again, the same thing happened.