Unfortunately, a refund is not possible. See the conditions of this ticket. Why do you buy tickets weeks in advance ?

Was a mistake I didn’t change the date.

this day I had to buy two tickets.

If you didn't download the tickets or loaded them in the app, then contact customer service. They may refund the if you ask nicely.

Unfortunately, a refund is not possible. See the conditions of this ticket.Why do you buy tickets weeks in advance ?

The website doesn't mention anymore that you can’t cancel. Mentioning this only in the conditions is not sufficient, as we all know from previous discussions.

I would like a refund for a ticket bought on accident 

I needed to buy a return ticket and not a ticket to leave

Unfortunately, a refund is not possible. See the conditions of this E-ticket. 

You can call NS customer service if you have not yet opened the ticket.  They will then decide on a refund.