I've had T-Mobile for over three years. I use them because the house I bought has no cell service and I knew they had calling/texting over WiFi capability. It worked great until May of 2014. Then all of sudden my texts would fail to send, and I wouldn't receive texts until hours, sometimes days later. People calling me were sent straight to voicemail. My calls out either cancelled after 2 seconds, or...and I know this sounds bizarre (I don't think TMobile believes me) I'd get a message in Russian. I could work around the problem by turning my WiFi off on my phone and then turning it back on. And it will work for about 5 minutes. Then same problems all over.
TMobile sent me a new phone in June to fix the problem. It didn't. They tried all sorts of things - none of which worked.
I chose to live with it, as frustrating as it was, but recently decided either the problem gets fixed, or I switch to Verizon (which now has cell service in the area, albeit not great). Called TMobile for one last attempt. They sent me a WiFi CellSpot Router and claimed it would definitely fix the problem. I set it up today. No change.
And, to clarify, my WiFi works great in all other ways. All my other devices are fine, including laptops, Roku, tablets. And on my phone (Samsung Galaxy Light) I have no problem with browsing, GMail, Facebook, etc... the WiFi connection is giving me access to the internet without any problems. I just can't call or text without the above issues.
So... can anyone help, or have an idea what is causing this very peculiar problem?