Unfortunately spammers such as these use a crawler program. They have the area code and the prefix. Then they just go down the list. Highlight the good numbers and cross off the bad ones.
got a call 09/08/2015 around 11.45am. They said they offer to lower the interest rate on my credit card. I was at work and had no time. They said the call later, but there was no call later. I believe they want only your credit card information, because they asked for a number on the back of the credit card.
They said that they wanted to lower my Chase card interest rate and kept asking me for the number, I said since you called me, tell me what is my name. No answer, beware. Scam.