How do i block third party purchases?

I'm trying to block prime citizen app and I can't do it 

https://www.t-mobile.com/support/plans-features/content-blocking

My daughter keeps charging apps on cell phone how do I block to stop this 

 I want to Block third party purchases

How much is the t mobile internet service every month 

I recently by accident purchases a app finder app I need to block it asap