Hundreds of t3 timeouts in a day

I have had 3 tech visits with the last appointment also including a supervisor. They updated and components of my coaxial line from ped to my modem. Still having countless t3 timeouts. Upload signal with drop out on the modem and no connectivity. Brand new modem and router. I have plugged LAN directly into the modem and see countless t3 timeouts and eventually it will disconnect. No help even after the third tech visit. Please help, internet service is down more than it works