Considering this knocks out home phone service, which means no E911 for 24 hours, I do not find this is acceptable in the least. Sure many have cell phones, but what if your home has an intruder in the middle of the night? I know for me, first instinct is to grab that home phone and dial 911.
But with your situation, that can't happen. Could be a life or death kind of thing. I agree with another poster that you should demand a credit and give this example as to why it is vital to have these problems (Especially digital voice) resolved immediately.
If I were you,
I'd write a letter to the Action Line at the Merc (email@example.com). This is the kind of thing they will print and put pressure on Comcast. It's unacceptable for someone at comcast to physically disconnect service (for no reason), which includes phone (E911), and then say you need to wait at least 24 hours for repairs (Reconnecting your service).