] I have a client who arranged a redelegation of their domain name hosting
] several weeks ago, but their old Internet provider hasn't updated their own
] DNS system to match.
] 
] The result is while the rest of the world can reach my client's Web site
] and send them e-mail, anyone who happens to be a customer of their old ISP
] cannot.
] 
] Several requests to the old ISP have gone unacknowledged and unheeded.
] 
] Can anyone suggest a course of action which might sting them into action?

Make sure that when your new client sends the request to the old ISP, that
the old ISP can clearly recognise the sender as being an authoritative
representative of their ex-customer, and that they can tell the old
ISP exactly what they need to do (eg: stop x.oldisp.net.au being a DNS
secondary for customer.com.au ASAP; or please secondary customer.com.au
from y.newisp.net.au effective immediately).  Have them CC: some technical
representative of their new ISP (probably you).

If they are not getting any response from email requests, try telephone.
They can ask whether the requests were received and when they can expect
the DNS changes to be made at the old ISP's end.  For all you know, maybe
the old ISP only has one DNS guy and he's on holiday at the moment.

If there's still no response, then find some current customers of the
old ISP who have been trying unsuccessfully to contact your client, and
ask *them* to request assistance from their ISP (who also happens to be
the one that can fix the problem).  They might have more incentive to
fix it when their paying customers ask them.
__________________________________________________________________________
 David Keegel <djk&#167;cyber.com.au>  URL: http://www.cyber.com.au/users/djk/
Cybersource P/L: Unix Systems Administration and TCP/IP network management