New Service installed and it sucks

New service installed today at 11am. Speed test was 14mbps with a 25 mbps silver plan. Now its 9pm and i can barely surf or load web pages as the speed is now down to 1.89mbps. My DSL service was at least a steady 2.5mbps

Called support 2 times and they claim network congestion and say sorry so many times my head is spinning. So i am about to rip this system out and get the dsl back