Remove my current Apple ID
I won’t be able to download app it’s asking me for a payment method and when add my credit card it still doesn’t work
You must update your payment method. If it is still not working when you've added your credit card make sure that the credentials are correct, that the region of the card and the region of your Apple ID are the same, and that your name is correct.
If this is all not working and the card is still being declined, please Contact - Official Apple Support to get further assistance on the matter