JamieB:
Yes I understand they missed the email, but why is there even an email to disconnect me, when I just got connected to a new provider.
Because Telecom have to notify Chorus you are no longer a Telecom customer, to ensure that Telecom do not get billed by Chorus for serving you. Whether it's HDs fault, or not, I don't know - perhaps it is Chorus who got mixed up internally.