Apex domains cannot have CNAME records.
Question and response
Question
dig hosted.co.za. NS
Answer
hosted.co.za. 4 NS ns.otherdns.net.
hosted.co.za. 4 NS ns.otherdns.com.
hosted.co.za. 4 NS ns.dns1.co.za.
hosted.co.za. 4 NS ns.dns2.co.za.
Authority
The response has no authority records.
Additional
ns.otherdns.com. 4 A 41.215.232.12
ns.otherdns.com. 4 AAAA 2001:19f0:7400:1a54:5400:3ff:fee2:36a5
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0