Had the same thing happen to me, just number came up no name, been getting many calls from this area code. The area code is an Arizon area code, have had 3 calls from that area code in the last 3 days.
Recieved several calls from this number and other 480 numbers in the past few days, they always hang up except for the last time. A man asked for me and then said nevermind and hung up. I never give my cell phone number out. It is through sprint, anyone else??