Infuriating sister! aarrgh!?

You just need to start locking all your stuff in your room so she doesnt take anything, second talk to your mom about the phone being locked in her room cause thats just ridiculous. As for what she says to your boyfriend and friends just tell them to ignore everything she says and since they are you friends they are going to believe you over your sister. I have a sister thats 17 too and she can be a pain in the *** too so your not the only one with an annoying sister.