Hi-my name is Hana with the Premier team.
Thanks for utilizing the Sprint Premier forum with your concerns! We strive for customer satisfaction and acknowledge all your questions.
From reading your post, seems like your child's like has become the primary line on the account? I apologize for any inconvenience you are going through. I understand your issue and I am glad to help. I could give you a few different scenarios to why your child's line became primary but I would rather give you the facts.
I have been trained on Premier as well as "change of a primary line" and am confident that I can resolve your issue. What I would need to do is access your account and than I can have more information in regards to why the lines were changed. As well as to get your line back as primary! If you can please send me a private message with your name, Sprint wireless number and 6-10 digit pin number.
I'll be looking for your private message and hope you allow me the opportunity to assist.
Thanks for being a valued Sprint Premier customer!
Anytime you change the Primary phone/line on your account the "System" automatically selects the next phone on your account as Primary, When they/you add your phone back they do not automatically make it Primary you have to request it. The system/rep does not know which line the account holder is going to use unless you tell them so they can reset it as primary. To get your phone reset as Primary you can call and request it, It takes 2-3 billing cycles to reflect the change.
Check out a fun infographic that teaches you how to increase storage, enhance security, improve battery life and clean your device.