"Experience, however, would seem to contradict this in that the mods actually do seem able to resolve these problems. Ergo, they would appear to have a method of easily contacting Openreach to explain a problem and asking for a resolution."
They do what the CS staff should really do - they take ownership of the problem and work with other departments. They have the experience to question responses that just can't be true . Same information but a desire to get to the correct answer and resolution.