If a credit/debit card payment is unable to process, you will receive a notification while creating a new booking of whether to retry the process of payment again or to change the payment method to cash or another credit/debit card.
First, retry to process the payment again, if the issue still presists you can reach out to your bank to identify the issue and resolve it.
Still not resolved yet? You can change the payment method to be cash in which the system will automatically add the negative balance directly to the upcoming trip, also, you can add credits into your account through which the payment will be deducted, or choose another credit/debit card (if existing).
