The Washington Post has a toll free number 1-800-477-4679 for all customers that wish to pay for their subscription with a credit card. They can handle all types of transactions involving all major credit cards.
The system is automated and your choices are as follows:
Press 1 - To start a subscription
Press 2 - For a missed or damaged newspaper
Press 3 - For a Vacation Stop with a re-start date
Press 4 - To Cancel your newspaper
Press 5 - To ask a billing question
Press 0 - To speak with an operator