I have a Samsung Galaxy S5, have had 4G for nearly a year. I noticed my rate drooped to 3G, and I can't get it back. I powered down, removed battery for a minute), removed SIM card, put back in, still 3G. I had a similar trouble before, the tech walked me through the same steps. I'm in an area where there is good 4G LTE coverage. I'm paying for 4G, I souls get 4G. Thanks