I have service with Walmart Family Mobile. They use T-Mobile network & are now owned by Tracfone. I just switched over to Tracfone & got the new SIM card. I chose T-Mobile compatible card because I get good coverage at home. Well, the phone doesn't work (iPhone 6s Plus) with the SIM card & Tracfone says that I need a Verizon compatible SIM. Another CS rep at Tracfone said that he thought that meant that the phone wasn't unlocked. That's what I was thinking. Based on the facts above, do you think that my phone is not unlocked. BTW this phone was purchased from Amazon as unlocked & worked with my Walmart Family Mobile SIM (T-Mobile. Thanks, Kev