Billing Dispute

My upcoming bill is charging me $100 for an in-person technician visit that happened because Comcast couldn't figure out how to activate my modem remotely. According to the technician, the issue was that the Mac ID typed in by the remote worker was wrong: the Mac ID typed in by the remote technician had incorrect letters in its Mac ID. I checked the chat logs of my text chat with the remote technician and confirmed that the Mac ID I gave him was correct: I correctly supplied the Mac ID, so the reason for the in-person technician visit was 100% Comcast's fault. I do not want to pay $100 for an issue entirely caused by Comcast. I would prefer to dispute the bill here, but I can issue a complaint with the FCC if that is a better way to get traction on this.