Gateway disconnects every day

My gateway has disconnected several times over the past 2 weeks. I've spent untold hours on the phone with support. Reset password to wifi password on router it then worked. But they said they've had a lot of issues with the Sage(?) router so they sent me their new Arcadyan router 3 days ago. Worked fine and this morning while online it went down. Called support and spent another couple of hours on the phone and he said the router isn't communicating with the tower. Router has all 5 signals and I'm only online now cause I connected with the ethernet. He said it's still not showing it's communicating with tower. He's put in a ticket for engineering to look into why the wifi isn't communicating with the tower. I now have to wait 3 days when he's back at work if he doesn't hear from engineering techs by 9 tonight?!  Good God! The first year we had t-mobile router there wasn't one problem, now it's a nightmare.