First off the original carrier of my phone is MetroPcs not T-Mobile. I saw that someone else asked about a MetroPcs phone issue and was helped so I thought I would give it a try. I am just about out of options. In Feb. of 2017 I bought a ZTE Zmax pro. I had MetroPcs service until May of 2017. I was able to have the device unlocked using the Device Unlock app. After the device was unlocked I switched to Straight Talk. I have been using this device with Straight Talk since. On Sep. 5 my service plan ended. I didn't have the money at the time to refill my service ( not the first time ). On Sep. 12 I bought a service card and added to my account with the Straight Talk app. When I checked the phone to see if service was restored and a message on the top of the screen saying invalid sim card was there. I turned the phone off and then back on like and tech would have told me to if i called. When the phone restarted a message saying Network locked to unlock the device go to the device unlock app. The message confused me but I went to the app as the message stated. When I opened the app the message Device is Permanently Unlocked was displaying. I viewed the history it showed the date I had the device unlocked. I contacted Straight Talk the agent checked my account and couldn't find anything wrong. The service card was added to my account. The agent said that it must be something with MetroPcs. I contacted MetroPcs and told them what was going on. I don't think she understood what I was telling her because I got the following e-mail the next day.