Sorry about the delay! One of those days where you draft but forget to send 
Just to confirm, the prepaid card won’t work with 3DS but with the current accounts, this won’t be an issue.
@Scoobyben Hey Ben! It might be better to get in touch with our support team so we can look at the details and see what went wrong. Few merchants force 3DS, so there could be another reason for it being declined.