We recently had a house guest who asked to use my phone. She is sending Facebook messages drom her Android phone that appear to be coming from me! This is causing serious problems! I want to catch her. I suspect she has also stolen items that could be used for identity theft. My device is an unlocked LG. I don't have a carrier, I just use our Wi-Fi. Her phone is also an LG through Boost Mobile. Any information would be greatly appreciated.