Yikes...That's particularly embarrassing because (a) it happened over 10 years ago, and (b) with most of the enterprise SIP trunking providers I know of updating CNAM records is pretty trivial. I know the provider I'm responsible for (and we're small fish with only about 50 DIDs) it takes 6 clicks and updates within an hour [though some providers cache it on their end so it can take a day or few before a change shows up "everywhere"]... but certainly not years. (I just did a CNAM DIP and got the same result so it's not your provider that's behind the times )