Credit Card Customer Service 800-285-6609 Monday – Friday, 8:00 a.m. – 6:00 p.m. (ET) 866-820-3947 After VACU Hours Credit Card Activation 800-527-7728 Lost or Stolen Credit Card 800-449-7728 24 hours a day, 7 days a week Lost or Stolen Mastercard® 800-627-8372 Within the United States 24 hours a day, 7 days a week 00 + 1 + 314-542-7111 Call collect from anywhere globally 800 Mastercard® Mastercard Assist Services Credit Card Payment Mailing Address Mastercard® P.O. Box 71050 Charlotte, NC 28272-1050