Beste antwoord door Stijn NS
Good evening curkeuc and welcome to the NS Community!
I'm sorry to read that you lost your backpack and that you're having issues with the lost item form. I'm not entirely sure why you're having these issues. Have you tried removing the cookies of your browser, or trying a different browser?
If all fails, you can contact our Lost and Found department via 030-7515155 (option 4-1 in the menu) or by sending a message via Twitter or Facebook. In general, you'd have to fill in the form first, but perhaps in your case they can make an exception.