I think if you have traveled recently, you will get calls from this number telling you that you have "won" a vacation. Of course they want your credit card number. I said I didn't have a credit card and they hung up on me.
I received call a few minutes ago and after quick research just added it to my silent ring contacts. I never call back numbers I don't recognize and wonder why some people do as noted above. If the call is important they will leave a message. If they don't, the call must not have been that important, i.e. it is a scam. Quit calling back numbers you don't recognize people!