About a year ago, since I worked from home in my basement and got crappy cellular reception, I tried turning on WiFi Calling on my iPhone 7+, and everything got better, also, I could then make calls from my other Apple devices (iMac, MacBook, iPad Pro), and all was fine. I also never got any additional charges from AT&T. About two months ago I started getting messages about it no longer working on my devices, and started having issues with my iPhone itself making calls (I could hear, but, called users couldn't hear me). The problem was not coincident to any Apple updates. I turned it off last week, and my iPhone has worked fine since then, even updated to iOS 11 with no issues. Was this something on AT&T's end? Have other users had similar issues, and were they just hoping that I'd pay additional fees or something? Thanks!