Flawed camera automatic update prevents Hotspot connectivity

For several weeks I have successfully used three each, second generation indoor cameras as a remote security system. All three cameras operated through a Hotspot. Two days ago I found two of the cameras disconnected from my hotspot around the same time. Shortly afterward, I saw the third camera receive an update and then fail to reconnect. Repeated attempts to reestablish a Hotspot connection were unsuccessful. I contacted my cellular provider (Verizon) and spoke with one of their technicians to determine if any changes in Hotspot connectivity had changed and was told no changes had been accomplished in the last few weeks. I removed all the cameras and Hotspot phone to my residence for further diagnosis. All three could connect to my in house Xfinity supplied wifi. I also determined all three phones could not connect to two other Hotspot units residing on the same bench as the cameras. I had a fourth camera, new in the sealed box, which i was immediately successful in connecting to my original Hotspot. As soon as the camera was fully activated it started downloading an update. When done with the down load, it no longer would connect to my Hotspot. A call to "technical support" was absolutely useless. I now have four useless cameras and a location burglarized twice, with no security.