I contacted the complaints department as per your link - received an email from the "CASE MANAGER" informing me to contact NBN Assurance....WAY TO GO "CASE MANAGER". You earnt your pay that day!
As per Clause 7.3 b of Telstra's Customer Terms, I have now notified Telstra in writing that it has breached a material term of our contract and Telstra now has 14 days to remedy or the contract is cancelled.
I suspect that in 14 days time, I will be using the NBN service with another provider.