when will tmobile improve its network, connection and coverage?

I have T-Mobile home internet and cell phone service. The internet is awful. I have called and troubleshooted many times and even had the modem replaced. The modem replacement did absolutely nothing to help. When I call to troubleshoot, it works great with an excellent signal for an hour at the most. For the last 2 months, around 9 pm the connection goes out and we have to reboot the modem. Cell phone service is also not the best. I have to get off of wifi when I’m in my home and making a call otherwise I get dropped and lose connection. I’ve called and troubleshoot this already too and it goes back to the norm after I hang up with the rep. When will T-Mobile fix their issues? I used to have Sprint and never had these issues on my cell service. Internet, ugh, it’s not getting better.