Can't watch U-verse TV

How Do I close out our AT&T account & what do we do to get the equipment back to AT&T? No one seems to care that we can't get the system to let us simply WATCH TV. I guess I'll tell the credit card bank people that FRAUD IS BEING COMMITTED  because we are being billed for services that we aren't able to access. When the installer left Tuesday 12/18 the TV worked OK, but after I turned it off it hasn't work since.