Apex domains cannot have CNAME records.
Question and response
Question
dig blendtek.com.au. NS
Answer
blendtek.com.au. 1 NS ns1.vocus.network.
blendtek.com.au. 1 NS ns2.vocus.network.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0