Who I have the same questioned this topic

I have had the following problem with two different iPhone 12 Pro Max phones over the past year, and now with my new iPhone 13 Pro Max.

I live in an area of poor cellular connectivity, and therefore rely on WiFi Calling when at home. When WiFi Calling is On, most of the time I can receive and make voice calls perfectly. However, about a third of the time WiFi Calling is not active, in spite of the fact that I can easily prove that my WiFi network remains well connected to the Internet, at around 25 Mbps, and that the iPhone remains connected to my WiFi network.

The way I can tell if WiFi Calling is active is to lock the screen, then tap once on the screen to illuminate it. If I see “VZW WiFi” in the upper left corner, then I can be 100% sure that I can make and receive calls; I have tested this hundreds of times over the past year. If, on the other hand, I see “Extended Network” in the upper left corner, I can be 100% sure than I CANNOT make or receive calls, though I can still access the Internet for anything else via WiFi. I will see “Extended Network” about a third of the time, but I have not been able to correlate it with time of day or anything else, it seems entirely random.

I understand that “Extended Network” means that the phone has connected to a non-Verizon network, with which Verizon has contracted to provide service when out of range of a Verizon cell tower. However: 1) the extended network to which the phone is connected is very weak, and incapable of supporting a phone call, and 2) if I have set “WiFi Calling” to ON, the phone SHOULDN’T BE ALLOWED to disable it and try the call on a (useless) extended network, or even on a perfectly good network, for that matter -- it’s SUPPOSED to always use WiFi for phone calls unless I tell it not to.

I can easily solve the problem, temporarily, by setting the iPhone to Airplane Mode when in my house; WiFi calling is never subverted by the appearance of an “extended network” if I do this, and voice calls go in or out perfectly, without exception. The problem with this is that I almost invariably forget to take the iPhone out of Airplane Mode when I leave the house. And really I shouldn’t have to do this anyway.

I have spent a couple of hours on the phone last winter with Verizon tech support, escalated a couple of levels, and they were unable to help me, after trying multiple solutions – resetting network settings, disconnecting and reconnecting to Verizon, and other things that I am not sufficiently tech-savvy to understand. After failing to help me, they insisted it was an Apple problem and there was nothing else they could do. I can’t prove that’s wrong, but if it is an Apple problem, it is a general one – it’s highly unlikely that I could have received 3 defective iPhones in the last year, several months apart. And if it were a general Apple iPhone problem, Google would quickly turn it up. Which it hasn’t.