Microsoft Office Home & Student 2019 change into Ofiice Proffesional Plus

I have bought a new laptop a year ago around august with free office home & student in it, well at first everything was fine until recently when i wanted to use ms words, it suddenly ask me for a key product, i thought my offics home & student was permanent but then when i checked the version it changed into office profesional plus 2019 and needs activation. This is so confusing, i dont remember to upgrade any office in my laptop-- or maybe i accidentally press the upgrade button without noticing it (?) I dont knoww--
My question is: is ther any way to change back my office into my free office home student so that it stops asking me for key product? It's so frustrating