This happened to me too. I've been getting calls all week / last two weeks regarding the same issue. twice from this number, a coule times from a restricted number, and once today from a 626 area code.
I thought my sister was calling from her boyfriend's place because his name is Cain and he lives in Tennessee so I assumed that 727 was their area code. Yet, I answered and it was "Visa" saying I've won a $500 shopping spree plus $40 of free gas. Seemed like a good idea so I played along. They knew the last four digits of the card and only asked to confirm who I was, they did not ask for personal information besides what they already knew which was name, address, and as mentioned before, the last four digits of the card number. I'm not real certain of the validity of this situation for it just happened and afterward I got a funny feeling, thus I found myself here. I did see other 727 area code numbers with the same problem, and I wanted to see if anyone else got a call from this particular number.