The App Store is not letting me download a free app without billing info

Ok so I have tried downloading a certain free game for at least an hour now. The window that keeps popping up saying verification required (specifically billing). I have tried removing my card info, updating it (it says my card info is invalid but I know for a fact it is valid), and when I try to add my card back on, it says it’s already on my account. I am very confused. Is there anyone who could give me an answer because I am just completely frustrated with this.