Upgrade Won’t Install

I installed the free plugin version of Multi Currency for WooCommerce and then pressed upgrade within the plugin, it took me to the page on EnvatoMarket, i paid for the upgrade, then it took me to the page to press download, so i downloaded the zip file, when i try to install the upgraded plugin it is saying this message:

Unpacking the package…
Installing the plugin…
The package could not be installed. No valid plugins were found.
Plugin installation failed.