I bought Minecraft-Java Edition, but they tell me that I can play only demo mode

Please check out this article: https://help.minecraft.net/hc/en-us/articles/360029643892-Can-only-play-Minecraft-demo-Java-Edition-

If that doesn't help, please contact Mojang Support.

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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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Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki
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