Clearly AS is noting each call, what you asked for and what was offered. That was reviewed by a manager and a determination was made that the ticket should never have been issued in the first place. Not much AS can do about that.
When you finally got the reroute offer, I would have jumped on it on the spot. Alternatively, there is no reason AS should change your ticket for free, but presumably your travel insurance will cover a ticket at least out of the danger zone.