You can write us anytime at:
Cardmember Customer Service
P.O. Box 6354
Fargo, North Dakota 58125-6354

Mail Payments:
Cardmember Service
P.O. Box 790408
St. Louis, MO 63179-0408

Overnight Address:
Cardmember Payments- 790408
824 N 11th Street
St. Louis, MO 63101-1016