A couple weeks ago I bought pico-8 to try and learn lua, but now I am stuck with the old version because it's not showing in my purchased products page. Any ideas? (I didn't use the weird 3rd party purchase save thing)

hiya! can you clarify how exactly you bought pico8?
there is itch, or lexaloffle (which uses humble for payment, not weird).

do you have an email with links?
or can you see pico8 on https://www.lexaloffle.com/games.php?page=updates ?