Alright, so I used to use a HTC M8 and I used H2O Wireless. It worked fine and I had no issues in my home or anywhere else. I've just recently bought the Samsung Galaxy S7 (Att) but I'm having problems with my cellular service but not data. I can only do emergency calls. I'm an ignorant young lad and don't really know what's the problem. I'm hoping you guys can tell me what's going on!