Where can I find an invoice (tax document)?

You find your invoice (tax document) in your customer administration account, as soon as we have received your payment on our account. Log into your customer account where the service is registered at
https://admin.forpsi.com/billing/list.php

In the section Invoices, there you find the list of all paid invoices. You can also search by the selected filters - e.g. variable symbol, kind of the service, or document.