Premium update removes original install

Hi all,
I have a premium account for multi site. (suing 2 currently)
On my both sites (live and test) I had installed the full package, but somehow it has gotten uninstalled on the test version. Now I tried to reinstall the plugin, which works for the first part as per support instruction witht eh downloaded version from UpdraftPlus. Than the plugin tells me to click on the update link to get the addon I had purchased, to enable site migrationa and cloning. that works fine, up to the point where nothing happens anymore on screen. When I refresh my screen, the plugin has been completely removed from the wo-admin plugin page, though the directory still exists on the ftp server.
Can anybody tell me what I doing wrong and lead me to a working full version of updraftplus?
I have this Licence type:Personal (up to 2 sites), so why is it not allowing me to install the premium version on both wp sites?
thanks..

Jako