Apologies for the trouble that you had to go through.
I have updated your records and you should be able to use your license now.
When you receive the message regarding trial or 30 days program, you should be able to choose the option "License this software" and activate using your key in order to use it without going for re-installation.
I have had a similar issue, and unable to find any assistance in the forums. I purchased the stand alone version of Lightroom 6, because I sometimes travel where I do not have Internet access. My online version (CC) always opens whenever I select to use Lightroom. I have never been able to get the standalone version to start up.
I purchased a disk version of lightroom 6 from B&H a few days ago. I was having problems trying to install the lightroom 6. It gave me an error 'download adobe support advisor.' Now for some reason it changes the resolution on the screen. I'm lost at the point. I need help.John H