The Web Client for the Transfer Website has a 4GB file size limit. However, you can directly connect to the FTP Server with any standard FTP Client and bypass this restriction. Review this article for more information.
Note: This assumes some familiarity with basic IT concepts.
You will need to configure your FTP client to use:
Protocol: SFTP
Hostname: transfer.micropay.com.au
Port: 2222
Username: [Client Number]
Password: [same as for the Web Client]
Here's an example from the popular WinSCP FTP Client:

