You tell them you power cycled the modem. They make you do it anyway. You ask them to do a traceroute and they either say "I don't know what that is" or "I can't do that" or "Yeah, we'll get to that after a few other things".
Last time I called, 20 minutes into the call he does a traceroute and finds the problem is a few hops from my house. Yeah, he wouldn't do it it first thing, so he wasted a bunch of time.
Sometimes, if they won't do the traceroute, they'll send someone out, in a 4 hour window, only to tell you when they get there at the problem is not near your house. Or, the problem is fixed by the time they arrive.
It's one of the most frustrating customer service experiences you can have.