Broken Sewer Line After Fiber Optic Work

A Comcast crew of about 8 people came to my house on November 9th to do some kind of upgrade for the fiber optics network which required jackhammering and digging near my sewer line at the end of my driveway. My toilet flooded on November 16th when my washing machine drained it's laundry water, and a plumber came out to inspect the issue on November 17th to find that the sewer line out of my house had become broken/disconnected from the main sewer line right at the spot where the Comcast crew was working. He is expecting the spot will have to be dug up again in order to fix the line and quoted me $4500 for the work.

I have a support ticket in for this issue already (expecting a call from Comcast about this sometime before 5PM November 19th according to the customer service rep that I talked to today) but I figured I would put the issue here as well since I saw others have posted about the same situation and they have gotten some feedback from customer service about resolving it.

Mainly I just want to make sure my support ticket is going in the right direction, and looking for guidance on what I can expect as an outcome here. (Like should I hire plumbers to fix the broken line and then ask for reimbursement? Or does Comcast prefer to arrange that themselves?)