Apple said I'm not an adult but I'm!!!

I want to use apple music family plan sharing with my friends, firstly, my friend registered but when he tried to add someone else, it shown "can't complete this time" all the time, so I did it my self, after I did pay the plan payment and tried to add someone more, it said I'm not adult, it said I have to be 19 years old...but I'm 19 years old!!! I don't know what to do, especially my money was gone, please tell me, what should I do?