Travis QuickPay and over-the-phone credit and debit card payments are optional, expedited payment services offered to provide additional levels of convenience. Travis CI billing system consists of two types of subscriptions: Concurrency (fixed-price) based plans and Usage-based plans.In the case of an overpayment or erroneous payment, a refund application is required. We are proud to accept Visa, MasterCard, American Express and Discover. Are add-ons limited to a certain number of users? Why is my credit balance negative?