Apple Payments

i was once using a debit card for payments but not using it anymore and I want to change payment method to none but it keeps saying I had subscription associated with my active so I then deactivated all subscription and deleted my card but when i try installing apps it says i should assign account to a payment which I don’t have any interest in assigning any card at the moment so my problem is that I want to change payment method to none but I’m facing difficulty in doing that.