AppStore Doesnt allow me to download

Hey apple community,

I have an iPhone 7plus running iOS 11.1. I cannot download any apps from the app store as it requires me to add my card details and when I do It gives me an error that I should try again later or that billing info is incorrect. I see on my apple profile here that my profile is set to the US, but I my phone is in Bulgaria. I didn't manage to find how to switch to Bulgaria here as it had only 10 or so countries.