Is the issue intermittent or constant?
Have you tried power cycling the modem? If not, please unplug the modem, wait about 30 seconds, plug it back in, wait about five minutes, then try to get online.
In addtion, if you have the modem plugged into a power strip or surger protector, try plugging it directly into an outlet to see if it makes any difference. Also, please make sure that the power plug that goes into the back of the modem is snug. Be gentle with this plug, as it's delicate, but it shouldn't be loose. Lastly, please make sure that the coax connector at the back of the modem is finger tight. It doesn't need to be any tighter, but it shouldn't be loose.
Did you accept the appointment for the tech on the 31st? I'm assuming you meant January 31st.