Payment method

I can't change my payment method I have my sisters card as the card on for payment method I don't know why tho I must have used it for something but whenever I go to remove the card the edit button is disabled I guess it won't let me press edit and remove the card (my sister does family sharing with me for apple music so idk if it's because she's my "organizer") the reason I want to remove the card is because whenever I make purchases in apps it takes money from her card and not my apple card I even have my apple card as the default card and it's the only card in my wallet is there anything I can do to fix this because I want to make purchases with my apple card but it doesn't take any money out of it