Typically private utilities such as sprinkler systems and dog fences are the property owners responsibility to mark and aren't covered under a one-call system to mark public utilities. Out of curiosity were the lines marked or contractors notified about the lines before the work was performed?
Your best bet would be to contact customer service on the issue who will generate a ticket for the local office to investigate and work something out with you.
I've asked a Comcast employee to help you. You should expect a reply in this thread.
speedracer702, I can help with your damage claim. Please send me a private message with your full name, address, and phone number tied to your residential services for help. Just click my name and then click private message me.