I have a problem with 4g on my G3. After about a few days of usage, my 4g indicator will have its up arrow lighted up and blinking, but the down arrow is not lighted up. When this happens I cannot access the internet on 4g. I have to restart the phone again, then the up and down arrow will be lighted up and I can use 4g again. I have the same problem with my old phone, a samsung galaxy s4. I have changed the sim card and the same issue persists.