Play demo

I am writing for my fifth time, because you keep doing nothing about it. You have send me robot answers, or taken me to a page that does not help at all.

I have bought minecraft for about 2 years ago. My name is CookieMedSprus, and I have migrated my account. But now in the launcher (I have tried the Microsoft Store launcher to) it says "Play Demo".

I have tried everything, please actually help me this time. I don't want to buy minecraft again, because I have already bought it.