Asking a bunch of strangers on the internet what you and a private party agreed to is silly.

That said, Comcast is a large company that can afford good legal advice to write their terms of service. Surely they thought about and covered such a contingency. I can't imagine they left themselves on the hook for any loss your business suffered due to an outage. Their liability is probably limited to rebating you for the outage time. But again, I'm just guessing, and all that is in your contract.

Olin is right. It seems unlikely that they would agree to a contract where you're entitled to business losses for interruptions. That doesn't prevent you from suing, but anyone can sue (almost) anyone over (almost) anything. They just typically lose.

If you have business-critical operations, you need to either (a) accept some level of down-time for things outside your control, (b) pay for a contract that covers contractual losses, (c) insure against downtime, or (d) get an additional provider line to cut to if the primary provider goes down.