MX and domain in separate locations

[Jonathan Villa]

I was hosting the domain isdesigndev.com with a hosting company who
managed the DNS information for me.I now changed to a hosting company
which has me maintaining the zone file myself.

Via the web, ssh, ping, whois, etc... the domain points to the new
nameservers, i.e. ns1.isdesigndev.com and ns2.isdesigndev.comhowever the
mail seems to be at the old location....I think this because I can view
my maillog on the old server and see everything getting rejected as
"relaying denied"...

Anyway, I tried to query the domain at the old location

dig isdesigndev.com ns1 @ apolloservers.com

and I get in return

;; ANSWER SECTION:isdesigndev.com.        4573    IN      A      
69.10.149.186

which is my new server...so, any ideas as to why my mail would still go
to the old server?

Do I need to check with the old hosting company to see if they have
"released" the zone file?  Do I even need to do that?  I changed the dns
info at the registrar level...