Sorry to hear you are having trouble yet again. I will definitely take a look at your system and run diagnostics - it is very possible we can save you the visit too and fix this together. Please allow me a little time to complete the testing.
I reviewed your previous cases while the tests ran and see that this exact problem has come up before, so I am not sure that replacing the modem was really what fixed the problem. Replacement modems come with a new ethernet cable, which appeared to be the issue the last time this happened.
After running initial diagnostics I can see that your HT1100 modem was plugged into an Apple Airport Extreme router. Can you confirm that the ethernet cable from the LAN port in the back of your HT1100 is securely plugged into the back of your modem and Apple router? Does the LAN light turn on if you plug it directly in to a laptop or computer?