I've asked a Comcast employee to help you. You should expect a reply in this thread.
FYI: They owe you a $20 credit for every tech visit after the first for the same problem. You can also get a credit for your service from the time you first reported the issue until it is resolved.
I can take a deeper look into this to see if there is some sort of signal issue or issues at the node that would contribute to the symptoms you are reporting. Please send me a private message by clicking on my name, "ComcastChe" then click private message me. In the body of this message please verify your first and last name, and the account number or phone number associated with your services.