I bought minecraft twice already and it won't let me join the premium servers, please fix this problem, a friend of mine did too

yesterday morning I bought Minecraft java edition. When I enter the launcher now it tells me that I can only play the demo, when yesterday it wasn't like that, I could easily play with my custom skin and on the premium servers. Also yesterday I clicked on the top left "Log out" and disconnected my account. The day after "Or today", when I log in it comes out that I can only play the demo. When I log into your site it also tells me that I have to buy the game, when I bought it Yesterday! Sorry for that English, I used google translate to make this.