Apex domains cannot have CNAME records.
Question and response
Question
dig net.cable.rogers.com. NS
Answer
net.cable.rogers.com. 5 NS ns3.ym.rnc.net.cable.rogers.com.
net.cable.rogers.com. 5 NS ns3.wlfdle.rnc.net.cable.rogers.com.
net.cable.rogers.com. 5 NS ns2.ym.rnc.net.cable.rogers.com.
net.cable.rogers.com. 5 NS ns2.wlfdle.rnc.net.cable.rogers.com.
Authority
The response has no authority records.
Additional
ns2.ym.rnc.net.cable.rogers.com. 5 A 24.153.22.142
ns2.wlfdle.rnc.net.cable.rogers.com. 5 A 24.153.22.14
ns3.ym.rnc.net.cable.rogers.com. 5 A 64.71.246.156
ns3.wlfdle.rnc.net.cable.rogers.com. 5 A 64.71.246.28
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0