NS Flex Dal Voordeel on OV-chipkaart

Hi, apologies for my English. Earlier today I purchased a NS Flex Dal Voordeel on OV-chipkaart subscription. However, the first time I tried to pay for it the website crashed and I didn’t think the payment went through so I tried again with a different card and had the same issue where I would be directed to the page “something went wrong”. However, I received two emails saying the payment did go through about an hour later and I now have the subscription but I think I may have the charge now on two of my bank cards and I would like to cancel one but I am not sure if that is possible?