After you buy ExcelPort, your purchase is associated with an iSenseLabs license code. You may find your license code in your iSenseLabs account downloads.
You can enter your license in Extensions > Modules > ExcelPort in the tab Support. This will activate your license and you will be able to receive premium support by the iSenseLabs support team.
Note ExcelPort will still work if you do not insert your license, meaning you are free to use it on your development servers. iSenseLabs support is granted only for domains where ExcelPort is activated.