How in the world did you find the correct phone number? And how did you pretend to be an employee? (Did you say "this is [random name, or maybe your own name] calling from Comcast?" or something?)
I did network event correlation in those days (using prolog and Perl to convert hundreds of thousands of log entries and events to actionable alerts), and would call various NOCs all of the time, usually to let them know that their device was spewing alerts or doing something dumb. There was very little in the way of authentication. Once you crossed the line to ask for things vs fix things you’d get more questions.
Yes, it is super hard now. It took over 5 seconds to find the Cogent support numbers:
http://www.cogentco.com/en/customer-service/support-desk
It if hadn't found anything after 10 seconds, I would have given up and gone back to watching Youtube.