I just ran a query on christiedigital.com from DNSStuff.
It's not saying that you don't have MX records; it's saying that it cannot get authoritative information on what your MX records actually are.
The "FAIL" on the MX Records Check seems to be a secondary error, caused for the same reason that it produces a "FAIL" on the SOA record check.
Neither the MX records nor SOA record can be obtained since it seems the NAMESERVERS cannot be queried.
This is consistent with my inability to query those nameservers using nslookup:
