What's wrong with my sisters phone?

I don't know what the helps going on, but someone was using my sisters phone to text people. It sent me, HELP THE PO PO GOT ME! And it texted her friend that he banged her mom last night. can someone PLEASE tell me what's happening and how I can fix it. It's really pissing me off!

Anonymous2015-05-15T15:20:18Z

Favorite Answer

Tell her to call the service provider and request the service to be barred. This way no further calls or text can be made with that sim

Fire2015-05-15T13:30:42Z

Somebody must have hacked it, it probably has a virus.