every night at 7 pm no connection

I have had T Mobile Internet since mid October and have had this problem all along. I got sick of calling customer service. We have been told they are updating their towers. The only reason we haven't switched back us the cost of other Internet Providers. I plan on going into the local store and talking to the manager, but I doubt they can fix the problem. For us, it's not only at night snd not only on their Gateway, but also on their cell service.