You cannot obviously ask for a refund for something that you know very well it always worked, and that is sold as TRY-BEFORE-BUY so, you are supposed to install it, test it and *then* purchase it, after you checked how it works on your system.
Also, since the activation log in the server shows you successfully activated the scenery 3 times (twice in 2016 and once 2017), it's a clear proof the scenery worked, otherwise it wouldn't even been possible to activate it.
So, the question is why is not working NOW. Are you using the latest installer ? If not, or not sure, download the latest installer from the website.
Assuming you installed using the most current installer, do you have the "Addon Manager" AND the "Couatl" menus under the "Addons" menu of the sim ? If no, the problem of missing menu items under the Addons menu it's usually caused by one of these:
1) Defective antivirus. Download and install with the Antivirus disabled AND configure the antivirus to exclude the whole Addon Manager folder from scanning BEFORE starting the sim.
OR
2) Missing/Corrupted VC++ libraries in your system. See solution in the "Addon Manager not showing up in P3Dv4 **SOLVED**" thread:
http://www.fsdreamteam.com/forum/index.php/topic,17484.msg122656.html#msg122656
