Sorry, I believe there is a misunderstanding here. What you have purchased from us is our self-hosted software, it is not a service in-of-itself. Self-hosted, means your server is self-managed (by you and/or your hosting provider). While we may access your server via FTP to aid in troubleshooting of our software (e.g. inspect files, software configuration, etc...), there are certain tasks which we will not perform and as a self-hosted customer rely on yourself to do so correctly. This would include uploading of files from the Client Area. If this is not something which you do not wish to perform or do not want to worry about, we do offer our Cloud offering which is on our infrastructure and we manage that for you here.
Our software support here is able to help outline some issues which may come up in self-hosting but you are responsible for performing/resolving the issues found. If you require assistance with what is discussed here (uploading files), please contact your hosting provider. In order to move on in our troubleshooting of an issue, these items we find would need to be done correctly.
For our support standards, you can of course, read the following document: https://invisioncommunity.com/legal/standards/