T mobile internet and data connection

So my internet keeps going in and out on the router. I follow the instructions on the router and it still keeps connecting to the internet and disconnecting. I have left it turned off all night and I still have the same problem. But also my data on my phone has also been a lot slower than it was when I first switched. I pay for the MAX plan so I don't understand why that is slower than it was unless Tmobile is having problems in my area with speed and bandwidth.