If you’re unable to pay against an allocated invoice number, it could be because the invoice has already been paid for or the invoice has been cancelled or you have indicated the # before the invoice number. i.e  #123456

In case you get an error when trying to make a payment, open your client area and check the invoice. It could be a paid or cancelled invoice. You can contact our support team to advise on the service you’re trying to pay for and if necessary generate for you a new invoice.