At some train stations, where multiple train operators run trains, there are different gates or poles for each operator. Did you perhaps check in at a wrong gate or pole?

Good afternoon Mahdi123 and welcome to the NS Community!

As Tochjo mentioned, it could be that may have checked in with a different operator. I would advise to contact our Customer Service. My colleagues can take a look at what exactly happened and perhaps correct it too. You can reach them by phone (030-7515155), via Twitter and Facebook, or you can start a chat conversation (option 'Chat with NS').