Unfortunately our payment partner MangoPay does not allow transactions with credit cards issued from all countries.
You can find the list of the authorized countries by following this link:
https://mangopay.desk.com/customer/en/portal/articles/2299163-which-are-the-authorized-countries-where-you-can-process-payments-
You won't be charged at all for the failed payments. Feel free to book again with a card issued from another country if possible. We plan to develop other payment methods in the future.