Who called from 2137973000

I am getting calls from this number, it rings and when I answer there is no one there and then there is a hang up.

Called 2 times today and did not say anything.

I just got a call from this number to.  I answered the phone and I said Hello and noone was there and I heard a hangup also.   Who are these people and what do they want?

just received a call from this number.  no message; they hung up after 2 rings

they called and wanted to know the last 4 # s of my credit card. and exp. date. When I handed over the phone to my spouse they hung up the phone. And you can't call them back. I called my bank and they told me that its some kind of scam.