Now that I wake up and think about it, you work from
home, so both your lines are in the same place. For most of us, this is
not true, but I see where you are coming from.
But my work uses my home Internet connection and a Sonicwall to establish a VPN between my office and the corporate network, so that doesn't help either.
I know how to connect to my firewall and get the status on the connection to the cable 'modem'. I know how to power-cycle my equipment, and if that doesn't work, I go in the other room and check the TV to see if the cable is good. If it isn't, I call Time-Warner, and if there's a long estimated wait time, I assume it's a wide area problem they already know about.
The problem is fundamentally no different from calling AT&T to tell them you have a problem with your phone service. That's not going to be from the line having trouble. I have 3 land lines here, (two paid for by the company) plus cell service on the Sprint network if none of those are good.