Costly trouble with Comcast Support

I want to relate my most recent and costly trouble with Comcast support.  Several weeks ago, my connection went down about a month after my speed was upgraded and a new modem installed.  I called support and went through the usual troubleshooting.  This was a Friday afternoon and I have voip phones so my phones were down as well.  They were unable to resolve the issue and scheduled a technician to come out Monday morning.  They said they would try to get someone out over the weekend if possible.  That did not happen.  I called my own people who came out to check the system. As soon as they walked in, the internet came back up.  They checked everything and all was well.  I knew that would not last and was again down on Saturday.  I called Comcast again but nothing was resolved.  On Monday, the technician installed a new modem and tried to get the internet up again.  I have a static IP and every time they loaded the IP, the internet would go down.  The first person was unable to get the internet up with the static IP loaded so they said it was on my side of the modem.  I had my IT person return again and check everything out.  He was unable to find anything wrong on my side.  He was on the phone with Comcast support for at least 5 hours with no resolution.  The case was sent to the next support level and they were supposed to give me a call. We left the modem provisioned without the sataic IP so that my internet was up.  

On Tuesday morning, the internet was up for about 10 minutes before it went down again.  Level 2 support decided to add the static IP without looking into the problem or calling me.  I spoke with basic support again and the first person said he could help me even though I tried to explain that we needed to have level 2 support.  Another technician was dispatched and he called before he came out to see what was needed.  He said the internet was working and the static IP was loaded.  He then asked what else was needed.  I told him that I wanted him to check the modem and IP.  He was very nice and helpful but told me that he could not check this because it was on my side of the modem. He did come out and did some work on the cable connectors and installed a device to lower the signal to proper levels. I again had my IT person come out and check the internet to verify the static IP address.  When he checked the IP, it was completely different from what the static address was supposed to be.  Apparently, the static address was loaded onto someone elses modem.  When we loaded the static IP, the internet went down again.  We requested a new address and after a couple more hours on my dime, we loaded the new address.  We have been up since then.  

I just received the bill from my IT company.  It was over $1000.  Who can I talk to at Comcast to help with this?  I should not be responsible for this as it was completely the fault of Comcast.