Please be more specific, which version of Sound Forge do you have? By voucher code, do you mean 'serial number' which you need to activate Sound Forge after installation. "Upgrading", is going to a new version.. 13 to 14 for instance. An update is free, typically to fix bugs and/or to add a new feature to the same version.
btw, this is a users forum and is not staffed by Magix employees so even the moderators do not have access to customer information. You may need to contact the Magix Customer Service Sales Team which handles sales and activation issues.
btw, double posting on the same subject is not allowed so your other post has been deleted.