@MojangSupport I already bought Minecraft Java Edition but I recently switched computers and after logging into my account, it's telling me I have to re-buy it. Please help.
I'm sorry you're having trouble. 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. If you haven't yet, please visit https://help.minecraft.net/hc/en-us/articles/360029643892-Can-only-play-Minecraft-demo-Java-Edition- … for a list of possible solutions.^AS