Family Sharing pay problem

Gary Bandy wrote:

Can I stop getting billed for app purchases by other members of my "Family Sharing Plan?"

Yes. Make sure that they buy and redeem gift cards to their own account that are sufficient to cover their purchases.

"If you're in a Family Sharing group, purchases are charged to your personal Apple ID balance. If you don't have enough Apple ID balance to pay for the purchase, the remainder is charged to the family organizer's primary payment method."

I am part of family sharing group, and bought gift cards but I still can't purchase, that account is dimmed. I also have apple pay and my own bank account but they no longer appear on the list of payment options. Family sharing is a great idea but might need a little refining for Grandmas!