Slow and inconsistent Internet speeds

For about three weeks my Internet has been very slow. I pay for the 1200 MB speed. I have spent lots of time with chat and live chat with little to show for it. The only thing chat and live agents seem to accomplish is setting up an onsite visit. I have had three onsite visits with no positive result. I did a speed test with a direct connection to my modem at the Xfinity incoming line outside my house. I told the last tech this on arrival. He still checked everything in all the house connections and said there must be a problem with the service at the street. That is what I had determined by direct plugging to my modem at the outside incoming line. He said the lines in the street were handled by a different crew and they should get to it in a couple of days. 

The problem has had the same answer for over three weeks. All the "troubleshooting" has done is waste my time.