S4U extension keeps making me pay again when I've bought it before

I’ve bought s4u components previously and I haven’t been on my sketchup for awhile while using rhino/revit and thought i’ll brush up on my sketchup extensions again but when I tried to click on my s4u extensions i keep getting a pop up box asking me to sign up with authorization code. I have no idea where did my authorization code when but I remembered paying permanently for the extensions.

any idea on who should I message for this trouble?

https://www.sketchupforyou.com/contact/