I want to change the payment card for my App Store, but I enter a new one and it tells me that I have a problem, it also doesn't let me change the region and country

I want to change my App Store but when I go to send, I'm going to enter a new payment method, it rejects it and says what an error other than that I'm trying to change the region and country it won't let me because I'm no longer in the same country . So I need to delete that card that says it has a subscription, but it doesn't and they put in a new one.