Can’t use Apple account balance

I’m trying to purchase something in a game for $20. I have $50 in my Apple account balance. It continues to try and force the purchase onto the card that’s hooked up, even though there isn’t anything on said card. I’m part of a family purchase plan, so I can’t add or remove any cards, but I have continually tried to leave and rejoin the family. When I leave the family, and try to edit the card, it says I cannot because I’m “not the head of the family” even though I’m not in one.