Thank you for the advice, I appreciate it!

It took some hunting around to find (for some reason when I open the plugin store there only seem to be a handful of plugins available, not including sketchucation tools) but after searching I found a link to it from a news item and then was able to download it and then when I tried to use the extension I again got the error message but the "help with licensing" button now brought me to a page where I could activate my license by searching up my copy of it, and now the extension works.

I recently purchased some plugin extensions, including the Fredo6 bundle, via Sketchucation. Initially I was able to activate them as instructed and I've been using them for a few weeks. But today when I tried to use one of them (FredoScale) I received an error message saying that my trial period had expired and I need to purchase a license, as if the perpetual license I already purchased is not being recognized, and I have not been able to figure out how to reactivate it. When I click on "manage licenses" (this button is part of the error message, see the first attached image) I receive a second message telling me I need to install Sketchucation ExtensionStore v. 3.1 or above. I'm 90% sure I already have that that though I'm not sure how to confirm that. It's all very frustrating.

Any advice would be most welcome.
If it makes a difference, I am using Sketchup 2017 and I do not want to update to a newer version.