Excellent signal, no connection

I had T-Mobile home internet for a little while at my apartment where I got mediocre coverage. Wasn't really too much of an issue. I could usually troubleshoot it.. as soon as I moved I spent over 6 months trying to troubleshoot including getting a whole new modem! They have a couple different brand modems. One of them is known for issues! The black one with the digital writing on the top was the one that gave me the most issues. I traded that one in. I think there was one by Nokia.. eventually I wound up leaving and just going to Comcast for 60 bucks a month because every ounce of troubleshooting and having them de-prioritize me regardless of telling me they weren't going to was just not worth it. I needed solid internet for my kids to do there online work at home. Their internet service is not quality