This is one of the numbers for Nationwide Credit, Inc.; a "zombie debt" collector:

Nationwide Credit, Inc.
2002 Summit Boulevard
Suite 600
Atlanta, GA 30319
1-800-456-4729

Other numbers include:

(212) 863-9911
(214) 613-5568
(313) 202-4478
(469) 656-7258
(770) 818-4023
(817) 349-3330
(817) 422-0170
(817) 422-0173
(817) 422-0166
(817) 422-0604
(817) 422-0567
(817) 717-6779
(866) 308-3838
(866) 659-0711

See:

http://www.ftc.gov/opa/1998/10/nationwide.shtm