This is a bit unclear.
As always: you can check-and do that first-on mijnNS what these charges are for.

Most likely is that you did not completely stop the subscription-this often also has to be done at some NS-yellow machine (ophalen bestelling).

If this does not give solution, then call/contact Service-centre

An item called € Klanten service (with a negative amount) is usually the balance that was taken from your card when activating NS Flex. You will get it back via your next monthly invoice.