You can log in through Stripe and change the payment method. The payment portal is accessible via the following link: Stripe Payment Portal.
Follow these steps to update your payment method:
- Log In: Use the email address that you used to sign the contract to log in.
 - Navigate to Payment Methods: Click on the "Payment Methods" tab.
 - Add Payment Method: Click on "Add Payment Method."
 - Choose Payment Method: You can choose between a SEPA direct debit mandate or a credit card.
 - Confirm Payment Method: Confirm the payment method by clicking the "Add" button.
 
Your payment method will be updated accordingly.