Unable to connect to Family Sharing Subscription

Hi there,

Recently I purchased a family subscription on Apple Music, so that each of us has an account. there was no problem setting it up on my mother's and father's phone (they never had their own subscription). However, my sister had an individual membership which expired yesterday and it does not seem to acknowledge that she is also in the family list. Only the message "Update your payment method" appears. On all other phones in the Family Sharing tab Apple Music is turned on-only on hers it is off and when she taps it it offers her to pay for a family subscription, which is absurd. We tried signing out of Apple Music, iCloud, Apple store and iTunes and still the problem persists. Does anybody have a clue why something like this would happen ?(she is on the family list)