@MojangSupport I’ve had Minecraft Java Edition for years now, but for some reason whenever I log into my account for the launcher, it says I haven’t purchased the game and can only play the demo version. I don’t know why it say this as I purchased the game long ago in like 2014.
When only the demo mode is accessible, this means that you're logging in with an account that does not contain a Minecraft profile/username. Please visit https://help.minecraft.net/hc/en-us/articles/360029643892-Can-only-play-Minecraft-demo-Java-Edition- … for a list of possible solutions. ^TM