This is great to see website are still accepting sponsoring even without paypal as main payment sources.
I don't know where they are based (I suppose china?), but some banks are blocking international payment with Visa.
For example France is blocking payment at USA's shops, I had to go to my back to give them order to not block it for that country.
I also had to do it for South Korea (with Ragnarok online).
I don't know about your bank, maybe it's not blocked at all and only France is making problem with outside-Europe shops.
That's a thing paypal didn't make problem as they had a bank in each county and it was viewed as national transactions for the bank.
I hope the new payment method won't make users go away from NDS-card.com