For the Netherlands
It is possible to add new orders to your Flex credit.
In your account, click on 'manage your order' to add an order.
Pay attention to the amount when you want to add an order
Only an order with an amount within your credit limit can be added to Flex. This is possible from the invoice date until the date of the second payment reminder. Once your credit limit has been reached, it is no longer possible to add the order to Flex. This also applies if you are already in arrears in your Flex credit or in one of your other Riverty accounts.
Useful links:
For which products can I use Flex as a payment option?
Information about the credit limit for Flex
How can I convert my account to Flex?