Payment is per order, and therefore per month (if you use a subscription). And otherwise just once of course. For the payment of an order, no further costs are calculated for the customer.
Do you have a subscription? Then your follow-up payments will be debited each time on (or around) the same date. Your order will not be shipped until we have received your payment.
Don't we manage to write off the amount? Then we will contact you. If you do not respond within 72 hours, your subscription will unfortunately be terminated.