Question [Q] No SMS while on WiFi??

Please tell me I'm not the only one with this issue!

For the past three weeks, I can't send/receive texts or even calls sometimes while WiFi is turned on. However, when I'm out and not connected to WiFi, there is no issue. I've tried calling T-Mobile but all they wanted to do was factory reset my phone. When I DO get phone calls, the other people seem as though they are breaking up and I can't understand them AT ALL. And when I do manage to send texts, they take forever to reach their destinations.

Anyone else experiencing this?