I'm not sure what else you could do, I think we all know Schiphol security is a mess.
Irrespective of secondary or not, never put anything on top of a jacket, that's a recipe for it getting lost, I always throw whatever is in my pocket under the jacket...

If you have a travel insurance, you can see if they might cover those expenses, though it might not be worth it for the sake of 11€, you could also request a refund from NS for those 2 days.