Ann: CEO Update and Appendix 4C - Dec 2016, page-8

Thank you very much for picking that up - my error entirely, I didn't fact check, tsk tsk.
Also, my unreserved apologies to Ted Pretty, it was my slip-up.
It was actually Nextgen that was referred to and not NextDC - you can see my erroneous Next conflation.

"Census 2016: Nextgen hits back at IBM claims

• 21 October 2016
• Written by Sam Varghese
• Published in Government Tech Policy

Nextgen Networks has hit back at IBM's claims that it was to blame for the census stuff-up, saying that its offer of protection against distributed denial of service attacks was rejected.
IBM accused both Nextgen and, through it, Vocus Communications, of not effectively implementing a geo-blocking plan that had been agreed upon to block foreign traffic from the census website in the event of an attempted DDoS."

..... The story goes on at some length - at the end of the day Nextgen/Vocus appear to have been cleared.

Once again, my sincere apologies.