So I have an interesting case with android... Before I start, yes I have done factory resets, I have even tried installing a new ROM. I have replaced hardware. I have replaced the SIM card. But I still have my issue with my phone and only with this specific phone. My Samsung Galaxy note 3 has connection problems connecting with my carrier. My carrier is Family Mobile which is a T-Mobile reseller. I also own four other phones between me and my family who are with the same carrier as me and I do not have the connection issue when I put my Sim in their phones. My issue goes as follows: My phone will randomly disconnect from data. I cannot send texts/call etc. And my phone is basically not longer registered on my carriers network. My APN setting are correct. Although sometimes but not every time when my phone disconnects, I'll see that its then registered on AT&T. Once I re-register on T-Mobile, the phone works for a short while. Sometimes when the last issue does not happen, I'll see a notification that says sign into T-Mobile and I'll click on it and push 'use-network-as-is' and the connection would work again for a short while. There's been a few times where the last two cases don't happen so I'll go into my APN setting and switch between two APNs that are registered to the same servers. Once I switch to the other APN, the networks works again for a short while, I have replace parts inside my phone and the phone still has the issue. This is the only connectivity issue that I have on my phone so that means, NFC and WIFI works just fine.