This is a scam. They claim that they want to lower your credit score. The other side is that IF you answer, they can somehow spoof your number and call anywhere in the world they want and not worry about the bills. The number above probably IS/WAS a legitimate cell phone number that the scammers have spoofed and have/are running up that person's bill. The person may have already changed their number, so it might actually be disconnected, but they have already spoofed it.....
REPORT IT TO POLICE AND TO THE FCC!

Credit  Card  Services  I  do  not  understand  why  in  the  hell  the  FCC  does  not  go  after  this  bunch  of  domestic
terrorist  that   irritate  the  hell  out  of  everybody  calling  everyday   using  phony  numbers  &  violating  the  no  call  rules.

I just got a call from this number at about 2:40 PM on July 3rd.  I ran the number here as it was ringing and saw that it was bogus.

Here is my tip to everyone tired of spam calls to their cell phones.  Set your default to be a no ring sound.  Then set the sound you want to people you want to talk to.  This way unknown calls ring through without making a sound and your friends and family will ring.

They only make it look like that is the number they are using, they are "spoofing" the number.  Their real number is concealed - sadly!

This number just called me 3 different times. no voice mail