What can I do if my iPhone is hacked and keeps sending international text messages?

My iPhone has been sending out international texts. Is it hacked?
Also I jailbroke my phone.
I'm using Tmobile( doesn't support iPhone)
So does anyone know how to fix it?

Go to a phone shop&explain what's going on&if they can't do anything, take your phone back+get a new one!

Complain on phone shop and give all details, may be they will be solved your issue