This happened a month ago, I bought Java edition and played it. When time passed by, I was only able to play the demo and I have to buy minecraft again. Mojang if you are seeing this please help me out on this one. Thank you!
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Thank you for your report!
We're tracking this issue in MCL-16570, so this ticket is being resolved and linked as a duplicate.
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Please refer to this article: https://help.minecraft.net/hc/en-us/articles/360029643892-Can-only-play-Minecraft-demo-Java-Edition-
If that does not help, please contact Mojang Support.
Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki