nothing wants to connect

My T-Mobile doesn't even show up when trying to connect a device. I've had to enter everything manually for each device. I couldn't get my old Roku to work,  so I got a new one. Still nothing. So I tried the onn brand at Walmart. Google TV. I had to manually enter everything, but it connected. My personal cell phone wouldn't connect, but my work phone did. I ordered security cameras a few weeks ago, and they won't connect at all. I've tried everything suggested on here. I went with T-Mobile to save money. Now I'm spending, even wasting money on things I can't use. How does that happen