I didn't get to my cell phone in time to answer. When I don't recognize a caller, I always Google the number first. I landed here after a call from this number just now, and, thanks to people's comments, I will not be calling back. Blocking from a cell phone is just too simple to try anything else.
WARNING--BEWARE!! These callers are B I G credit card criminals, known as the card service scammers! Under NO circumstances, give these lowlifes your credit card number, or you will regret it forever!