Minecraft demo although bought game?

Naaa I bought the 20 euro version of Minecraft on ps4 but it shows that I only had the demo because someone knows a solution?

Did you register with the right account?

Uninstalling the demo and installing the full version would be my first thought.

There are different possibilities.

What I would do if I were you:

Start anew
Reinstall Minecraft
maybe you have installed a demo and not the full version
write to Minecraft Support

I don't think the demo will be a full version. You have to install them separately.