In order to change the payment method for your Deutschlandticket, please follow these steps:
Cancel your current subscription. Don't worry, there won't be any extra cost.
Create a new subscription with your desired payment method.
Please note that changes to the payment method can only be made before the tenth (10th) of the month. Your ticket for the current month will still be valid.
If you only need to purchase the ticket for the next month, you can start the ticket purchasing process again. You will have the option to enter your new credit card details and complete the payment.