Amen! That's what I've been preaching! You have to prove them wrong even when they are "right"!
It's been inband signaling to alert of toll fraud in the nearest tandem switch the whole time. The tandem switch has been detecting the "beep" as some old-time pay phone fraud signal. The frequency of the "beep" was just right to be interpreted as such. The good news is that this single toll switch affects dozens of local central offices, even non-Verizon ones, so many problems have likely been solved with your collective handful of customers.
Think of the thousands of customers who may have had this same problem. I shudder to think of the ones who gave up and replaced their systems because........Well you know what I was going to say.
