Technician Costs

I had a technician come out to the house because I was having issues with the wifi connection going in and out and then no internet at all. The technician checked my line outside the home and stated that I was back feeding into the cable line because of my bad electrical. He said he has seen fires because of things like this. I contacted and electrician who came out after hours because I was worried we were going to have a fire. The electrician found nothing and explained everything he was checking and doing. I contacted Comcast for another technician visit and within 5 minutes he said we had a bad modem and replaced it with no more issues. I contacted Comcast to cover the $330+ bill from the electrician that I ABSOLUTELY had to have come out from the fear of a house fire that the comcast technician told me I would have. They refused. So my question is, what is the next step I need to take in legal action against Comcast? Does anyone know the legal or Comcast office address I would send a letter of demand to?