You can set this up in your payment methods in your Mobile Vikings account. You can choose between Visa, MasterCard or direct debit.
Do you have a prepaid SIM card? In that case, you can use your payment method for your top-ups, or even use it to top up automatically or via sms. If you have a subscription your invoice or payment invitation will be paid with your payment method. If you have Viking Points, these will be taken into account first.
How does the direct debit payment work exactly? When you make a payment (for a top-up, invoice or payment invitation) it takes about 6 to 12 days for the payment to go through on your bank account. Even longer in rare cases. If the payment for whatever reason doesn't go through, your remaining calling credit will be revoked. If you have a subscription, the invoice or payment invitation will be marked as 'unpaid' and you'll be asked to pay for it manually. Your payment method will be blocked as well. Discover what to do if your direct debit has been blocked.