Apex domains cannot have CNAME records.
Question and response
Question
dig mtel.net. NS
Answer
mtel.net. 5 NS ns2.mtel.net.
mtel.net. 5 NS ns.mtel.net.
Authority
The response has no authority records.
Additional
ns.mtel.net. 5 A 213.226.7.34
ns2.mtel.net. 5 A 213.226.7.35
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0