cambio regularly bills you for your trips, fees and other costs. Until the next invoice, cambio pays these costs in advance for you. This is what the credit limit is for.
Your credit limit shows how much you can still use until your next regular invoice. After the invoice, your agreed credit limit is fully available again, provided your payment and usage behaviour is reliable. It may change over the course of your contract and can be adjusted to your level of usage.
Your credit limit must be sufficient for any booking. In the my cambio portal you can check your current credit limit at any time. If it is not enough to complete a booking, you can buy driving credit to increase your available credit limit.