For many years I've had great coverage when visiting Stoughton, WI (53589), better than my home area in IL.
A few months ago I first observed a weird problem in which I had full bars on my phone, but could not make or receive voice calls. I got a great LTE signal, internet connection and could surf the web just fine.
I contacted T-mobile support when I got home to IL (couldn't make a call while in the trouble area), and chalked it up to network problems that day.
The next time I was in that area, I again could not make or receive calls on my iPhone 5s, yet could make calls from a borrowed Alcatel Go Flip 3 (on my account).
So I called T-mobile support from the Alcatel phone, and was on the line with them for a long time, and the person finally said they were going to 'switch me to a different cell tower', and that I should power cycle my phone and then wait a couple hours, and it should work fine (this was in the 1-2 AM time period).
I knew this was a load of crap, as I worked in the cellular industry for 30 years as a software developer on the network side, cell site, and even handsets, but it was late a night, and I didn't have the incentive to give the person a hard time. Of course it was still not working the next morning.
When back in my home area, I called T-mobile support again, and explained the problem. This person, after a long time, said they compared the SIMs for the two phones I had used, and had 'normalized' them, and that everything should be fine then next time I was in that area.
So, the next time I was in the area, there was still no voice service. This time I put my iPhone into the 'Field Test Mode', and did some checking.
Saw great LTE signal strength, but absolutely no GSM 2G/3G signal (for a fleeting moment I detected a neighbor cell, but its signal was way way down in the mud). I did some research on my phone, and found that my iPhone 5s does not support Voice Over LTE, so with only an LTE signal, I was not going to be able to make or receive calls! (Why didn't T-mobile support tell me this? They knew what type of phone I was using.)
On my way home, I found that once I got a couple miles outside the Stoughton, WI city limits, I again had an adequate GSM signal, and could make voice calls.
Again, while back in my home area, I called T-mobile support, explained the situation, and asked why there had been no notification of the removal of 2G/3G service in that area, why there was no information on the T-mobile web site warning users of the removal of service. The response, after getting escalated a couple of levels, was that they were doing 'tower work' and replacing 2G/3G radios with 5G, and that typically users of affected phones that had mailing addresses within the affected area would get notified.
Ok, fine and good, but what about the T-mobile customer that doesn't live there, and is traveling through the area?
If I had a medical emergency while in that area, I would not be able to call for help, even though my phone says I've got great coverage, and would simply die.
T-mobile needs to notify ALL customers that 2G/3G service is being turned down NOW. They should put a 2G/3G coverage map on their web site (like the 4G/5G map that they so proudly display), and keep it updated as the coverage area shrinks.
The current lack of information shows a total disrespect for the lives of their customers.