Why doesn't my power button works, is shutted down and can't be opened

Hello. My samsung galaxy a7 2018 model isn't turning on. Earlier, it was still on and the button started to not work and then it shutted down. Now, it's only charging and I can't open it. I tried holding the volume down and the power button together, doesn't work. I also tried connecting it to my pc and it still didn't work. I can't also take the battery out. Please help huhu my parents will kill ms once they find out that this happened. I can't afford a new one huhu