NOTE : The problem has repeated itself. So this doubles as an off the cuff case study in level 1 troubleshooting, looking at data, comparing information at different locations. Also - I wrote it, and I'm not wasting my time by not publishing it. I have the Samsung Galaxy A12, and the service through T-Mobile is pretty good. While the infrastructure around our nation is fair at best, it's showing it's age and weakness in storms - and that may apply to private towers owned by T-Mobile as well. I turn on data, and either: It works The symbol in the upper right does not show up and it's not working. The symbol shows up and the data still doesn't work. Here's a demo; Other videos are available upon request. Now, there is a setting where I can change the mobile band (2G/3G, 3G/4G) my phone uses, something I was unaware of until a cool Twitter user let me know. This alleviates the problem sometimes, but if I go hours without using data, the problem returns....