I have a sneaky feeling that someone else has hacked into either my account or my phone number. This morning, my uncle called me and said that I called him 4 times in the middle of the night. I told him I never made such a call, but after he hung up, I checked my phone and found that I made NO calls to him during that time. I am worried because sometime last week, I was browsing on my phone when the network suddenly vanished. and only returned after I restarted the phone. I have changed my password but how can I change my PIN? Also, I want to have a 3-step verification; how do I do that?