I have a Samsung Galaxy 10E and I live in a secure building. Visitors press a code on a keypad, it rings on my phone. I press 9 or 99 and the buzzer to the front door goes off to let them in. For two years, I have had no trouble with letting people in. Last week, it did not work. Hours (literally) with the Verizon tech, hours with the manu tech of the keypad, both say must be the other's fault. Shut my phone off, did any updates, took out the sim card. No luck. Turns out only 2 other people in my bldg have the same problem. They have iphones. Only connection is we have Verizon. Others in the bldg have ATT and no problem. Advice?