New modem problems

I had Xfinity television and Internet service about 1 1/2 yrs ago. I left due to monetary issues and started with AT&T...
the worst decision ever, and I learned their service is the worst in the world ---so limited and I don't want to pay $200 a month for a little amount of channels and 0 support.
I chose to go back with Xfinity. I received my modem, wires, etc., yesterday Saturday.
There was no remote control in the Box. !!!!!!
So that was one problem right away.
I spent time chatting with 3 agents and no one could figure out why my phone which is a Samsung Galaxy 8 would not reconnect.
I had connection at the very beginning of all this and then something happened and now there is no connection.
The agents went through everything from rebooting my television
my modem
my telephone
restarting the service stopping a service unplugging waiting 60 seconds
plugging back in.
Nothing is working to restart my cell connection.
I would love to hear others' ideas of what I can do.