Monthly charge for “HINT P11”

Notewriter wrote:

 Was charged $17.33 this month for “HINT P11. 
¿Qué es esto?

Appears to be $20 off T-Mobile Home Internet.

This cost was actually an additional charge to my account, not a credit?

My monthly charge was $17.33 higher this month than past month?

I may have to call “T-Mobile?” 
Gracias.