These ISPs all record their calls for "quality assurance purposes", so the idea that there's no record outside of the customer's own to whatever they promised is ludicrous. If we're not doing so already, I think it's time to keep records of all our calls.

I believe there are some places where this might be a legal hiccup, but I'm not sure if those rules still apply if the other party informs you that they're recording it themselves.