@MojangSupport when I login to Mojang I am told that I need to buy Minecraft when I already own it. Help

If you can only play Minecraft demo, please visit help.minecraft.net/hc/en-us/… for help.

I rarely use tweet and have never replied so I sent you a new tweet before figuring this out. I am using the full version and have no problem login in to the game itself. A few month ago, this same happened and I finally gave up and purchased a new one.