comcast will not repair internet service

Our business Internet service has been down for over six weeks. The highway department replaced a storm water culvert across the road from our facility and cut the underground Internet service cable to our facility, causing the loss of service. 

I have called Comcast Business support five times over the past six weeks and have been promised each time by Comcast Business support that the problem would be repaired. No repair has been performed.  I have also repeatedly asked for refunds on our monthly Internet service bill, since the service is down, and no refund has been made.

I have been PROMISED repeatedly by Comcast Business support that this problem would be fixed. All promises have been broken.

How can I escalate this support issue so that our Internet service can be restored? Anyone know? If I had any other Internet service provide option in my area, I would take it. I am stuck with Comcast...