Mobile Data isn't working!
I have an iPhone 6 Plus 16GB, model A1522. I live in Brazil and I use Vivo as my carrier.
Here's what happened...
Earlier this year I had a Galaxy Note 4. I didn't like TouchWiz so I found a guy on 'eBay' that accepted my Note 4 on his 6 Plus. We made the deal, and I now had an iPhone.
It worked great, everything was smooth and I had zero issues. Then, one day (about 1.5/2 months after the deal) my iPhone stopped calling, receiving calls, texting and receiving text. Those functionalities were gone but at least my LTE connection still worked.
I learned to live with it. I didn't even called or texted that much anyways. But, **** got serious when I travelled to Las Vegas and when I returned to Brazil I activated mobile data only to find out neither the 3G or the LTE icons would appear on the top-left corner. I tried everything. Even a full wipe and I also tried with other sim cards aswell. The only time I managed to make it work was when I inserted my sister's sim in my iPhone, then removed and inserted mine back again. Then I'd put it on airplane mode for 10 secs and when I deactivated airplane mode I had mobile connection. As soon as I turned off mobile data and turned it on again the problem would come back and I would have no internet connection, having to repeat the sim swap process.
Help would be very appreciated!