No authority for domain

[Tommy]

"dig authority machinename" does not show authority when run from a shell
on my isp.  Is there any other way for me to determine what they believe
is the athourity for my domain.

There is a discrepency between my zone file and queries to my isps dns
server, (they are supposed to be my secondary)  I thought perhaps the
serial numbers got messed up, or they might have themselves incorrectly
set as the SOA.  If I can't get a there dns server to tell me what can I
do to investigate this.  Thanks