mx.ezbing.com has no NS records.
NS records for this zone are defined at ezbing.com.
NS records for this zone are defined at ezbing.com.
Question and response
Question
dig mx.ezbing.com. NS
Answer
The response has no answer records.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0