I'm sorry to hear this. Based on your screenshot, it seems like you're not the owner of a Premium for Family plan, and you're just one of the members. Members of a Premium for Family plan aren't able to invite or remove any other members on the account.
In the meantime, you do have access to Premium now, so enjoy ad-free content and unlimited listening! If you need help with anything else, just let me know :)
Billy-JRock Star 16
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