Thanks people

You don’t need to top up. With NS Flex all costs (both travel costs and subscription costs) are automatically deducted from your bank account each month.

FLEX ALWAYS means it is a current subscription-that gets renewed every month-and if you want to change it/terminate then you have to act yourself- via mijnNS and via the site, not app.

The money due for the subscription has to be paid advance-and after 1 month are added the cost for incidental travel-also bustram, if done in the month passed. You get a mail some days before the day-always the very same day of the month.