DataFax invoices net 14 (that is invoices are due 14 days from the date of the invoice). Customers may pay their invoices by check or money order sent by mail or by credit card. DataFax accepts American Express, Discover, MasterCard, and Visa. To pay with a credit card please fill out the credit card authorization form and fax or mail it to us. Please review our Refund, Exchange, and Cancellation Policy.