My position was recently terminated, and as a result of that I had to turn in my company phone. I had the Facebook app installed on my phone, and since the firing came as a complete surprise, I did not think to either delete the app of log out prior to turning in my phone. Another ex-employee of the company heard from someone still at the company that I had been let go and messaged me via Facebook to have a bit of a "gripe session" about the boss. The boss saw all of the conversation on the company phone and is now contacting me saying that I am defaming the company. He also responded to the other ex-employee through the Facebook messenger on my phone. I've heard that the boss is also planning on firing the person who told the other ex-employee that I was let go. Since the Facebook app was on my work phone, does that mean that the boss has a right to read and respond to messages that came in? Or do I have a reasonable expectation of privacy since I never gave him permission to access my Facebook messages?