I just got off the phone with MegaPath. I spoke with a live tech (the hold time for the queue was only around 4 minutes or so this time around) and told him that from the voicemail [name withheld] had left me I'd gotten the impression that he was taking full responsibility, and that such a thing was not my intent. I told them it wasn't the mistake that the tech made that was the problem, it was the lack of business-class response on the part of MegaPath. I'm a net tech, and I know that mistakes happen (and have made more than my share in my years). The guy on the phone said he thought it was really admirable what I was doing, and that he'd update the ticket with that clarification. I asked if I could be transferred over to the tech who'd spoken with me on Saturday, and was told he was done for the workday, but that I could leave a voicemail. I said I'd like that very much, and so I got bounced to his voicemail and left him a long, rambling message explaining where I was coming from, why I was upset and (most importantly) what I was really upset about. I told him I didn't blame him (I also clued him in where he went wrong with my IP filter configuration) for the problem, I was just upset that when I called back to get it fixed nobody was taking up the slack on the tech support line's queue. When I was done, I said I hope he accepted my apology and that he has a good day.
I feel worlds better now.
Thanks to urocyon and roho for convincing me to take this course of action.