After payment, we are waiting for notification from the payment system about a successful transaction.
During this period you can refresh the confirmation page and see no changes in status. In this case, please don't worry. You can't pay twice, because the invoice issued to your registration can be paid only once.
From our side, we do monitoring of new registrations and in case of stucked payments, we process them manually.
So if you see no changes in the status of your payment please wait a bit or contact us via creating a ticket.