Hello
I am the first visitor in Netherland and I found out that it is convenient to use NS app and buy ticket. So I tried to buy ticket from Airport to Amsterdam RAI but after buying a ticket I could not find the ticket in the NS app "my tickets". So i tried two times more. But finally I looked up my e mail and I have already buy 3 tickets just for me. So i want to refund 2 tickets. I asked the train ticket box staff about this but she answered me to give it a call to you service center. How can I get refund for 2 tickets? Please let me know.