Mail will not be delivered at Mondays in the Netherlands. Today is possible.

Good morning Mehdi bensouar and welcome to the NS Community.

If you haven't received your card yet by the time your NS Flex subscription is supposed to commence, please contact our Customer Service. My colleagues won't be able to help you with the card delivery itself, as that process is handled by the OV-chipcard company, but they can provide you with necessary information, and they can provide you with alternative means to use the discount of your subscription. I would recommend contacting them by Chat or phone at this time.