Hi.

Some of them are configured to hang up if you are on hold for too long (!!!!).

Yeah, I absolutely hate those. I mean what is the point with that? They are only causing someone who waited for a long time to have to line up at the end of the queue again.
"As you waited for too long, we will now hangup trying not to tax your patience too much."
Now if that doesn't tax my patience too much, what else could do so?

cu,
sven